Moved LSSTErrorModel to rail_astro_tools

[jfcrenshaw]

Change Description

This PR addresses this ticket in rail_astro_tools, by moving the LSSTErrorModel degrader to that repo, and removing the explicit error model implementation by just wrapping the error model in PhotErr.

~Note these tests will fail until the associated PR the associated PR in rail_astro_tools with the new LSSTErrorModel is merged.~

Oops! I was wrong! I needed to remove all the LSSTErrorModel imports in this repo -- the tests here don't know anything about rail_astro_tools.

[codecov[bot]]

Codecov Report

Patch coverage has no change and project coverage change: -2.17% :warning:

Comparison is base (91adfec) 97.53% compared to head (cdd18fc) 95.37%. Report is 7 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #35 +/- ## ========================================== - Coverage 97.53% 95.37% -2.17% ========================================== Files 28 28 Lines 1585 1493 -92 ========================================== - Hits 1546 1424 -122 - Misses 39 69 +30 ``` | [Files Changed](https://app.codecov.io/gh/LSSTDESC/rail_base/pull/35?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC) | Coverage Δ | | |---|---|---| | [src/rail/stages/\_\_init\_\_.py](https://app.codecov.io/gh/LSSTDESC/rail_base/pull/35?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC#diff-c3JjL3JhaWwvc3RhZ2VzL19faW5pdF9fLnB5) | `100.00% <ø> (ø)` | | ... and [4 files with indirect coverage changes](https://app.codecov.io/gh/LSSTDESC/rail_base/pull/35/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC)

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[jfcrenshaw]

This PR only removed the LSSTErrorModel (it has been moved to rail_astro_tools), but, because that code was all covered by tests, removing those lines of code decreased the fraction of lines in this repo covered by tests. This is blocking the merge. Is it possible for someone to override this?