feat: Add prototype code for validating fragement file

[Bento007]

Reason for Change

• prototype cellxgene schema CLI changes needed to validate fragments single-cell#721

Changes

• add cli command

$ cellxgene-schema validate-fragment -h                                                                                                    
Usage: cellxgene-schema validate-fragment [OPTIONS] H5AD_FILE FRAGMENT_FILE

  Check that an ATAC SEQ fragment follows the cellxgene data integration schema. If
  validation fails this command will return an exit status of 1 otherwise 0. When
  the '--generate-index' tag is present, the command will generate a tabix
  compatible version of the fragment and tabix index. The generated fragment will
  have the file suffix .bgz and the index will have the file suffix .bgz.tbi.

Options:
  -i, --generate-index  Generate index for fragment
  -h, --help            Show this message and exit.

• add requirements to run dask in local distributed mode
• add validation steps for ATAC-SEQ fragment file
• add tabix index generation steps.

Testing

• TESTS NEEDED

pip install git+https://github.com/chanzuckerberg/single-cell-curation/@tsmith/10x-ATAC#subdirectory=cellxgene_schema_cli

Remaining Work

chanzuckerberg/single-cell#724