Update convex hull code

[christinawlindberg]

1. Updated convex hull path with concave hull method to make it possible to fit fields with concave footprints. Regular convex footprints are still fittable with this method.
2. Create a diagnostic plot to visualize the area where ASTs can be placed. E.g.

[christinawlindberg]

Would fix #779

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 17.94872% with 32 lines in your changes are missing coverage. Please review.

Project coverage is 42.16%. Comparing base (bcc8cb5) to head (fe8373a).

:exclamation: Current head fe8373a differs from pull request most recent head a3eb4c3

Please upload reports for the commit a3eb4c3 to get more accurate results.

Files	Patch %	Lines
beast/tools/cut_catalogs.py	17.94%	32 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #789 +/- ## ========================================== + Coverage 42.00% 42.16% +0.15% ========================================== Files 108 107 -1 Lines 10275 10135 -140 ========================================== - Hits 4316 4273 -43 + Misses 5959 5862 -97 ```

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[galaxyumi]

I tried this on LUVIT galaxies, which have more complicated footprints from multiple cameras as well as more significant density variation within one HST pointing. Unfortunately this doesn't fix the problem reported in #779. Also, the shapely package version seems to affect its usage. The version @christinawlindberg used was 2.0.1 for her development.

[karllark]

@christinawlindberg can you response to @galaxyumi's comment above?

[karllark]

Closing. New PR will be opened base don a branch.