Filter stack and radial covar optimizations

[garrettwrong]

Converts code towards filter stacks while maintaining ability to use legacy single filters (for now).

Provides a to_radial method for Filters.

Provides means to mix most singleton and stack filters. Vectorizes bulk evaluations.

Tries to vectorize (and sometimes use GPU when things fit) for filter_statck_to_basis_mats.

Add code paths to run radially optimized filter_stack_to_basis_mat.

Adds a smoke/timing test for covar2d using 10028 (ribsome) and 11618 (ctf per image) experimental sized cases.

Still a WIP, need self review.

[codecov]

Codecov Report

❌ Patch coverage is 84.65608% with 58 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.45%. Comparing base (24ad316) to head (c743b13).

Files with missing lines	Patch %	Lines
src/aspire/operators/filters.py	74.83%	38 Missing ⚠️
src/aspire/basis/fle_2d.py	74.50%	13 Missing ⚠️
src/aspire/basis/ffb_2d.py	96.22%	2 Missing ⚠️
src/aspire/basis/steerable.py	90.47%	2 Missing ⚠️
src/aspire/covariance/covar2d.py	97.87%	1 Missing ⚠️
src/aspire/numeric/cupy.py	85.71%	1 Missing ⚠️
src/aspire/source/image.py	95.23%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1388      +/-   ##
===========================================
- Coverage    90.68%   90.45%   -0.24%     
===========================================
  Files          135      135              
  Lines        14663    14926     +263     
===========================================
+ Hits         13297    13501     +204     
- Misses        1366     1425      +59     

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