Custom annotation addition (e.g. LoqusDB)

[hassanfa]

Is your feature request related to a problem? Please describe.
Custom annotation for recurring variants from external sources, (e.g. LoqusDB) so we can either pickup technical noise or variants of same type for same cancer.

Describe the solution you'd like
If possible, a clear and concise description of what you want to happen.

Describe alternatives you've considered
None yet. TBD.

Additional context
TBD.

Expected output for the feature
Annotation in VCF

Current BALSAMIC version
4.1.0

[hassanfa]

This is too vague and detailed. Specific DB annotations will be added as individual issues, e.g. cbioportal, gnomad, clinvar, etc.