Required to build an updated subscriptions management UI.
Most of the diff is generated proto for some reason
Closes https://linear.app/sourcegraph/issue/CORE-226
## Test plan
Integration tests
This directory is the root of a separate go module from the primary module rooted at sourcegraph/sourcegraph. This module exists to hold code that we want to reuse outside of the sourcegraph/sourcegraph repo.
Code in this module should not import from sourcegraph/sourcegraph or from other Sourcegraph repositories to avoid complicated dependency relationships. Instead consider moving code from elsewhere into this module.