Next connectivity scripts

[EmmaRenauld]

Cleaning:

• scil_connectivity_compare_populations: already clean! simply trying to clarify the help!

• scil_connectivity_normalize: already clean! simply trying to clarify the help!

• scil_connectivity_reorder_rois: already nearly clean! simply trying to clarify the help! Some code was written twice; simplified.

• scil_connectivity_compute_pca: This script was not yet written with scilpy's standard. Bigger cleaning.

  • simplified loops in cases where numpy can do it in one call
  • simplifed mask usage
  • separated the functions for plotting just for an easier read.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 92.70833% with 7 lines in your changes missing coverage. Please review.

Project coverage is 69.41%. Comparing base (e6775d5) to head (cf57e30).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1063 +/- ## ========================================== - Coverage 69.41% 69.41% -0.01% ========================================== Files 447 447 Lines 24045 24034 -11 Branches 3280 3278 -2 ========================================== - Hits 16690 16682 -8 + Misses 5960 5958 -2 + Partials 1395 1394 -1 ``` | [Components](https://app.codecov.io/gh/scilus/scilpy/pull/1063/components?src=pr&el=components&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=scilus) | Coverage Δ | | |---|---|---| | [Scripts](https://app.codecov.io/gh/scilus/scilpy/pull/1063/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=scilus) | `70.23% <92.70%> (-0.04%)` | :arrow_down: | | [Library](https://app.codecov.io/gh/scilus/scilpy/pull/1063/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=scilus) | `68.30% <ø> (+0.04%)` | :arrow_up: |