Added landsat8 collection2 support

[s-kowa]

Current version of raster.py uses metadata group names based on Landsat Collection 1 data (obsolete). This revised version checks the collection number from the MTL metadata file and uses proper group names depending on the collection number.
MTL changes are documented in "Landsat Collection 2 Level-1 Product Metadata Fields", which can be accessed at USGS: https://www.usgs.gov/media/files/landsat-collection-2-level-1-metadata-additions-and-changes

[s-kowa]

Fixed a bug in my previous commit, i.e. different group names between Landsat 8 vs 5-7 -> "TIRS_THERMAL_CONSTANTS" vs "THERMAL_CONSTANTS" were not considered for collection 1 data, hence causing a unit test error.

This issue has been resolved in my latest commit.

In additon, I included an iterative search for the collection number inside the MTL metadata file. This allows for an easy expansion towards additional collection numbers in the future. Group names are defined based on the found collection number and exceptions are treated as AttributeErrors.

I missed to set the black formatting line length to 120 in my earlier commit. This has been fixed in my latest commit.

[codecov]

Codecov Report

Patch coverage: 83.87% and project coverage change: -0.76 ⚠️

Comparison is base (d2bbf2e) 96.16% compared to head (9d0c8db) 95.41%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #173      +/-   ##
==========================================
- Coverage   96.16%   95.41%   -0.76%     
==========================================
  Files           6        6              
  Lines         548      567      +19     
==========================================
+ Hits          527      541      +14     
- Misses         21       26       +5     

Flag	Coverage Δ
unittests	95.41% <83.87%> (-0.76%)	⬇️

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Impacted Files	Coverage Δ
ukis_pysat/raster.py	93.23% <83.87%> (-1.98%)	⬇️

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[fwfichtner]

That looks good, I guess we can do it like that. Thank you very much!