Update LSIF documentation and associated CI workflows
Created by: shrouxm
lsif.yml
shows what an LSIF workflow looks like with the new recommended CI setup.
The main doc update is the addition of language specific guides. Also removed references to lang servers and made a few small changes throughout the code intel doc tree.
Once this is merged I'll work on trying to write a campaign to get all of our repos indexing with the same method #10137 (closed)
Closes #9289 (closed)