feat(rpc/auth): add OIDC auth method service gRPC definition (#1138)

* feat(rpc/auth): add OIDC auth method service gRPC definition

* chore(rpc/auth): rename authorizeURL to authorize_url

* chore: empty commit to kick CI

* fix(rpc/auth): remove state from authorize url params

* refactor(rpc/auth): adjustments to OIDC signatures

* fix(rpc/auth): typo in operation_id

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>