anchor links for lexicon groups in repo overview page #16

it's cool how collections under a single 2ld are grouped, but imo it would be even cooler if the groups had linkable ids. basically i would like to link to all my leaflet related records with a url like https://pdsls.dev/at://did:plc:fxnw2wkzf23zya6shq4pxvh6#collections:pub.leaflet