Modify DGV annotations to more general tab format to support complex SVs

[zhemingfan]

Overview

Currently, the Summary module takes in a tab delimited file (similar to a .bed file) as the input. For future iterations, we want to change it to a MAVIS .tab file format so that more information is included.

• Change support in summary from tab delimited file to MAVIS file format, rename DGV to "known_sv" as SVs from more databases will be added
• Add column for support for frequency of which a variant is observed
• Add unit tests for data that pulls from external and internal Nanpore databases (decide on TSV or VCF file formats to support)
• Add unique ID support to delineate which dataset a call is from