authz: remove FetchRepoPermsByToken, add options to repo sync
Created by: bobheadxi
Partial follow-up to https://github.com/sourcegraph/sourcegraph/pull/23978 - no real functionality changes here, mostly interface adjustments:
- Makes the necessary Provider-level changes to add cached repos sync (to come in a follow-up)
- Removes
FetchRepoPermsByToken
(added in https://github.com/sourcegraph/sourcegraph/pull/23018) - somewhere along the lines it seems all external usage of this was removed (removing it from the Provider interface did not break anything). All implementations have either been privatized or removed entirely. This allows us to add account ID information to the GitHub provider's token sync for caching.