Release browser hail tables

[rileyhgrant]

Resolves #1369

Adds a help page (à la the v4 hail table help page) that describes the gnomAD browser hail tables (variants, gene models).

Reviewing this PR mostly entails taking a glance over the help text to see if there's anything incorrect or misleading.

[rileyhgrant]

Files to sync are:

• gs://gnomad-v4-data-pipeline/output/genes/genes_grch37_annotated_5.ht
• gs://gnomad-v4-data-pipeline/output/genes/genes_grch38_annotated_5_no_constraint.ht
• gs://gnomad-v4-data-pipeline/output/gnomad_v4/gnomad_v4_variants_annotated_4.ht

[nadeaujoshua]

Hey this looks good. I flagged what looks like a few typos.

[ch-kr]

thank you for adding! I've added some minor comments and suggestions, mostly to help clarify the descriptions

[rileyhgrant]

Thanks, all, for the comments. Going to be working through them right now.

Thanks especially to KC for your patience, and for going through this whole blurb of text multiple times now.

[ch-kr]

a few more minor things -- thanks for your patience with my nitpicks!

[rileyhgrant]

Hiya @ch-kr, this should be ready for your re-review, at your convenience.

Apart from addressing the comments there's a few added things (downloads page with placeholder links, the changelog post , and documenting of the VRS annotations and the joint frequency annotation).

Thank you!!

[ch-kr]

thank you for adding the downloads! a few more minor things, otherwise LGTM. the one thing that needs updating is in data-pipeline/src/data_pipeline/data_types/gene.py (it looks like a bug to me)