Relicense to Apache Version 2.0

[djhoese]

We've got full approval in #105 from past contributors. This PR switches the license to Apache Version 2.0. I also removed two scripts that were in the root of the repository that I think were accidentally added a long time ago and are not Python 3 compatible.

• Closes Relicense to Apache Version 2 #105
• Tests added
• Tests passed
• Passes git diff origin/main **/*py | flake8 --diff
• Fully documented

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.75%. Comparing base (8e50a9b) to head (3ccdf6f).
⚠️ Report is 17 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #114      +/-   ##
==========================================
+ Coverage   88.69%   88.75%   +0.06%     
==========================================
  Files          20       20              
  Lines        1521     1521              
==========================================
+ Hits         1349     1350       +1     
+ Misses        172      171       -1     

Flag	Coverage Δ
unittests	88.75% <ø> (+0.06%)	⬆️

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[coveralls]

coverage: 87.907% (-0.1%) from 88.027%
when pulling 3ccdf6f on djhoese:relicense-apachev2
into e654689 on pytroll:main.

[mraspaud]

LGTM, thanks for pushing this forward!