Flatten directories

[marcpaterno]

This PR flattens out most of the deep directory hierarchy.

It is backward-compatible to allow code that used the older, deeply nested, module structure. Use of that form for the imports produces deprecation warnings.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 95.90444% with 48 lines in your changes missing coverage. Please review.

Project coverage is 98.2%. Comparing base (9105119) to head (dbb28ea). Report is 11 commits behind head on master.

Files with missing lines	Patch %	Lines
firecrown/likelihood/number_counts.py	89.5%	18 Missing :warning:
firecrown/likelihood/statistic.py	91.1%	11 Missing :warning:
firecrown/likelihood/two_point.py	97.5%	7 Missing :warning:
firecrown/likelihood/weak_lensing.py	95.3%	6 Missing :warning:
firecrown/likelihood/gauss_family/gauss_family.py	0.0%	4 Missing :warning:
...recrown/likelihood/binned_cluster_number_counts.py	98.5%	1 Missing :warning:
firecrown/likelihood/gaussfamily.py	99.3%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #424 +/- ## ======================================== - Coverage 98.3% 98.2% -0.2% ======================================== Files 36 46 +10 Lines 3167 3223 +56 ======================================== + Hits 3116 3167 +51 - Misses 51 56 +5 ``` | [Files with missing lines](https://app.codecov.io/gh/LSSTDESC/firecrown/pull/424?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC) | Coverage Δ | | |---|---|---| | [firecrown/connector/cosmosis/likelihood.py](https://app.codecov.io/gh/LSSTDESC/firecrown/pull/424?src=pr&el=tree&filepath=firecrown%2Fconnector%2Fcosmosis%2Flikelihood.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC#diff-ZmlyZWNyb3duL2Nvbm5lY3Rvci9jb3Ntb3Npcy9saWtlbGlob29kLnB5) | `97.2% <100.0%> (ø)` | | | [firecrown/connector/numcosmo/numcosmo.py](https://app.codecov.io/gh/LSSTDESC/firecrown/pull/424?src=pr&el=tree&filepath=firecrown%2Fconnector%2Fnumcosmo%2Fnumcosmo.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC#diff-ZmlyZWNyb3duL2Nvbm5lY3Rvci9udW1jb3Ntby9udW1jb3Ntby5weQ==) | `99.7% <100.0%> (ø)` | | | [firecrown/likelihood/gauss\_family/gaussian.py](https://app.codecov.io/gh/LSSTDESC/firecrown/pull/424?src=pr&el=tree&filepath=firecrown%2Flikelihood%2Fgauss_family%2Fgaussian.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC#diff-ZmlyZWNyb3duL2xpa2VsaWhvb2QvZ2F1c3NfZmFtaWx5L2dhdXNzaWFuLnB5) | `100.0% <100.0%> (ø)` | | | [...s\_family/statistic/binned\_cluster\_number\_counts.py](https://app.codecov.io/gh/LSSTDESC/firecrown/pull/424?src=pr&el=tree&filepath=firecrown%2Flikelihood%2Fgauss_family%2Fstatistic%2Fbinned_cluster_number_counts.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC#diff-ZmlyZWNyb3duL2xpa2VsaWhvb2QvZ2F1c3NfZmFtaWx5L3N0YXRpc3RpYy9iaW5uZWRfY2x1c3Rlcl9udW1iZXJfY291bnRzLnB5) | `100.0% <100.0%> (+1.4%)` | :arrow_up: | | [...ood/gauss\_family/statistic/source/number\_counts.py](https://app.codecov.io/gh/LSSTDESC/firecrown/pull/424?src=pr&el=tree&filepath=firecrown%2Flikelihood%2Fgauss_family%2Fstatistic%2Fsource%2Fnumber_counts.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC#diff-ZmlyZWNyb3duL2xpa2VsaWhvb2QvZ2F1c3NfZmFtaWx5L3N0YXRpc3RpYy9zb3VyY2UvbnVtYmVyX2NvdW50cy5weQ==) | `100.0% <100.0%> (+10.4%)` | :arrow_up: | | [...likelihood/gauss\_family/statistic/source/source.py](https://app.codecov.io/gh/LSSTDESC/firecrown/pull/424?src=pr&el=tree&filepath=firecrown%2Flikelihood%2Fgauss_family%2Fstatistic%2Fsource%2Fsource.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC#diff-ZmlyZWNyb3duL2xpa2VsaWhvb2QvZ2F1c3NfZmFtaWx5L3N0YXRpc3RpYy9zb3VyY2Uvc291cmNlLnB5) | `100.0% <100.0%> (ø)` | | | [...hood/gauss\_family/statistic/source/weak\_lensing.py](https://app.codecov.io/gh/LSSTDESC/firecrown/pull/424?src=pr&el=tree&filepath=firecrown%2Flikelihood%2Fgauss_family%2Fstatistic%2Fsource%2Fweak_lensing.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC#diff-ZmlyZWNyb3duL2xpa2VsaWhvb2QvZ2F1c3NfZmFtaWx5L3N0YXRpc3RpYy9zb3VyY2Uvd2Vha19sZW5zaW5nLnB5) | `100.0% <100.0%> (+4.6%)` | :arrow_up: | | [...own/likelihood/gauss\_family/statistic/statistic.py](https://app.codecov.io/gh/LSSTDESC/firecrown/pull/424?src=pr&el=tree&filepath=firecrown%2Flikelihood%2Fgauss_family%2Fstatistic%2Fstatistic.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC#diff-ZmlyZWNyb3duL2xpa2VsaWhvb2QvZ2F1c3NfZmFtaWx5L3N0YXRpc3RpYy9zdGF0aXN0aWMucHk=) | `100.0% <100.0%> (+8.8%)` | :arrow_up: | | [...own/likelihood/gauss\_family/statistic/supernova.py](https://app.codecov.io/gh/LSSTDESC/firecrown/pull/424?src=pr&el=tree&filepath=firecrown%2Flikelihood%2Fgauss_family%2Fstatistic%2Fsupernova.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC#diff-ZmlyZWNyb3duL2xpa2VsaWhvb2QvZ2F1c3NfZmFtaWx5L3N0YXRpc3RpYy9zdXBlcm5vdmEucHk=) | `100.0% <100.0%> (ø)` | | | [...own/likelihood/gauss\_family/statistic/two\_point.py](https://app.codecov.io/gh/LSSTDESC/firecrown/pull/424?src=pr&el=tree&filepath=firecrown%2Flikelihood%2Fgauss_family%2Fstatistic%2Ftwo_point.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC#diff-ZmlyZWNyb3duL2xpa2VsaWhvb2QvZ2F1c3NfZmFtaWx5L3N0YXRpc3RpYy90d29fcG9pbnQucHk=) | `100.0% <100.0%> (+2.4%)` | :arrow_up: | | ... and [12 more](https://app.codecov.io/gh/LSSTDESC/firecrown/pull/424?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC) | | ... and [1 file with indirect coverage changes](https://app.codecov.io/gh/LSSTDESC/firecrown/pull/424/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC)