add hyperlinks to Equivalent IDs on gene pages

[lwinfree]

It would be good to have each external IDs hyperlinked to their original source on gene pages.

For example, HGNC, OMIM, Ensembl, & KEGG links here:

(from page: https://monarchinitiative.org/gene/NCBIGene:6622).

These links seem to exist on disease pages, but not always (from minimal searching).

[jmcmurry]

1. For those not in the loop, just wanted to clarify that the above means linking out to respective sites, not internally within Monarch, as that would be circular.

2. Moving forward, as a general rule, I'd like to de-emphasize the identifiers from the UI. This doesn't mean I'm opposed to linking out to the respective (external) source data; that is fine. Just that we are currently treating identifiers as some of the most important information there is to find. Identifiers should be always findable, but not front and center. Hope this makes sense. Also any time we are linking outside the monarch site we should be doing so with the linkout icon so that the user knows what to expect.

[lwinfree]

👍 to all of Julie's comment