build: Need a config to ignore test data

[lsetiawan]

@madhavmk brought up a point that currently test datasets might not be ignored in the built code... need a way to ignore these. One way is to use config with Manifest.in file to ignore.

[madhavmk]

The point of concern is the large size of the ./tests directory, which causes the gnatss source distribution tar file to be unnecessarily large. In the future we are likely to increase the ./tests directory size significantly by adding additional data files. `

[SSEC/offshore-geodesy]$ du -sh * 4.0K LICENSE 0 MANIFEST.in 12K README.md 844K docs 4.0K noxfile.py 4.0K pyproject.toml 140K src 15M tests

[SSEC/offshore-geodesy]$ python -m build ... [SSEC/offshore-geodesy]$ du -sh dist/* 44K dist/gnatss-0.1.dev106-py3-none-any.whl 4.7M dist/gnatss-0.1.dev106.tar.gz `

After excluding the ./tests directory from the build step, the source distribution file reduced in size significantly. This speeds up gnatss pip installation speed due to faster downloading, and lesser unzipping. `

[SSEC/offshore-geodesy]$ du -sh 4.0K LICENSE 0 MANIFEST.in 12K README.md 844K docs 4.0K noxfile.py 4.0K pyproject.toml 140K src 15M tests [SSEC/offshore-geodesy]$ python -m build ... [SSEC/offshore-geodesy]$ du -sh dist/ 44K dist/gnatss-0.1.dev107-py3-none-any.whl 788K dist/gnatss-0.1.dev107.tar.gz `

[madhavmk]

MANIFEST.in file is used only when using the setuptools build system. However as mentioned in the pyproject.toml we are using hatchling build system instead. We can therefore remove this MANIFEST file. Reference