Prep BCF for pypi upload.

* Refactored the BCF dir into a "src-layout" which I am more comfortable with. We can likely change this back if it is not compatible with other development

* I added a few setup files for the bcf package (setup.cfg, pyproject.toml and a MANIFEST.in file)

* Added two __init__.py files in the v2 and v3 subfolders for them to be picked up during package compilation

.github/workflows/ci.yml

@@ -68,10 +68,11 @@ jobs:
           sudo make -j $(nproc)
           sudo make install
 
-      - name: install xmlschema
+      - name: install dependencies
         run: |
           sudo /usr/bin/python -m pip install -U pip
           sudo /usr/bin/python -m pip install xmlschema numpy
+          sudo /usr/bin/python -m pip install src/bcf
 
       - name: Test
         run: |