ci: disable automatic deploys to dogfood, running e2e tests against dogfood
Created by: ggilmore
This PR should not be merged until https://github.com/sourcegraph/infrastructure/pull/699 gets the final approval.
As part of the plan described in https://github.com/sourcegraph/sourcegraph/issues/976, we're disabling auto-deploys to dogfood and e2e testing against dogfood until the follow-up work has been completed.
This PR:
- Disables automatic deployments to dogfood
- Disables e2e testing in CI against dogfood
- Documents how to run e2e tests locally
- Disables e2e tests that depend on the go language server (which currently can't be run locally until @chrismwendt 's work on that is completed)