Remove legacy resampler code

[djhoese]

Satpy depends on a new enough version of pyresample that all of theses imports are guaranteed.

• Closes #xxxx
• Tests added
• Fully documented
• Add your name to AUTHORS.md if not there already

[codecov]

Codecov Report

Merging #2610 (dc3ee7d) into main (0f339d1) will increase coverage by 0.12%.
The diff coverage is 100.00%.

❗ Current head dc3ee7d differs from pull request most recent head 59c8b94. Consider uploading reports for the commit 59c8b94 to get more accurate results

@@            Coverage Diff             @@
##             main    #2610      +/-   ##
==========================================
+ Coverage   94.94%   95.07%   +0.12%     
==========================================
  Files         354      354              
  Lines       51487    51370     -117     
==========================================
- Hits        48886    48839      -47     
+ Misses       2601     2531      -70     

Flag	Coverage Δ
behaviourtests	4.23% <80.00%> (-0.04%)	⬇️
unittests	95.69% <100.00%> (+0.12%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
satpy/resample.py	89.32% <100.00%> (+9.52%)	⬆️

[coveralls]

Pull Request Test Coverage Report for Build 6617341206

• 10 of 10 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.1%) to 95.642%

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Totals
Change from base Build 6614128955:	0.1%
Covered Lines:	48962
Relevant Lines:	51193

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💛 - Coveralls

[djhoese]

Oh I like the 0.1% increase in coverage 😉

[mraspaud]

LGTM!
Nice with all the removed code!

[djhoese]

Oh no! I just pushed one more commit that failed tests lol. Shoot. New PR incoming... lol

Sorry, my fault for trying to throw in one more commit.