VLE/KBE-34/routing_of_merging_data

[Akaud]

Add routing_merge function to merge LOVD and gnomAD datasets

• Implemented routing_merge function that merges data from two sources:
  • LOVD data (from lovd_path)
  • gnomAD data (from gnomad_path)
• Added file existence checks for both LOVD and gnomAD data sources
• Created necessary directories if they don't exist in the save path
• Handled data parsing and merging:
  • Extracted and merged relevant fields from LOVD "Variants_On_Genome" and "Variants_On_Transcripts"
  • Merged gnomAD data with LOVD data using merge_gnomad_lovd
• Added an option to prevent file overwrite when overwrite is set to False
• Included error handling for file saving

[Strexas]

Move to backend folder.