Several updates for the LRG portal

- Fix for LRG transcripts in the GRCh37 database
- Add links to matching variants and their minor allele frequencies when available. Update the locations, using HGVS notation ('Reference comparison')
- Update the legend and highlight the LRG exons in the sequence ('Reference comparison')
- Remove the module Component/LRG/LRGSummary.pm (no useful information)
- Menu: move the page 'Reference comparison' under the 'Sequence' menu and remove the panel 'LRGSummary' from the LRG summary page