Update S2 L1 tests for masking

[jeremyh]

• Expand the test datasets, as the packager now needs to read L1 data files for masks, not just the metadata.
• Support for Sinergise package layouts, to fix the Sinergise tests.
• Skip masks that are too small have data (fiona doesn't like the gml files ESA provides that are null)

[codecov[bot]]

Codecov Report

Attention: 35 lines in your changes are missing coverage. Please review.

Comparison is base (a666bca) 84.78% compared to head (6c84222) 84.38%. Report is 4 commits behind head on develop.

Files	Patch %	Lines
eodatasets3/wagl.py	67.28%	35 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #321 +/- ## =========================================== - Coverage 84.78% 84.38% -0.40% =========================================== Files 26 26 Lines 4410 4503 +93 =========================================== + Hits 3739 3800 +61 - Misses 671 703 +32 ```

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