fix: Revert "feat(github): forkOrgs, forkCreate (#18770)"

docs/usage/self-hosted-configuration.md

lib/config/options/index.ts

lib/constants/error-messages.ts

lib/modules/platform/github/index.spec.ts

lib/modules/platform/github/index.ts

lib/modules/platform/github/types.ts

lib/modules/platform/types.ts

lib/workers/repository/error.spec.ts

lib/workers/repository/error.ts