Add glob pattern and path support for SHEETS_IGV_OMIT_*

[mikkonie]

Discussed with @Nicolai-vKuegelgen. The IGV file omission settings need to be updated as follows:

• Allow glob patterns with e.g. wildcards for the file names to be omitted
• Take in consideration the full path below sample_data for each file, instead of only the file name
• Existing values without patterns can be considered to have an asterisk in front of them, e.g. omit.bam becomes *omit.bam. They'll still work the same way
• Defaults in the Django settings should be amended with an asterisk.

Unless I'm missing something major, this seems like a very trivial update to make and it could be easily fit into the current v0.14.2 release.

Notes

• Refactor get_igv_omit_override()
• Modify check_igv_file_name() into check_igv_file_path(), provide path instead of name

[mikkonie]

Done.