Grab AUTHORIZATION_CODE_EXPIRE_SECONDS from oauth2_settings
rather than hard code.
Add REFRESH_TOKEN_EXPIRE_SECONDS to valid_key_names
in OAuth2ProviderField class
Credentials now have a required CredentialType, which defines inputs
(i.e., username, password) and injectors (i.e., assign the username to
SOME_ENV_VARIABLE at job runtime)
This commit only implements the model changes necessary to support the
new inputs model, and includes code for the credential serializer that
allows backwards-compatible support for /api/v1/credentials/; tasks.py
still needs to be updated to actually respect CredentialType injectors.
This change *will* break the UI for credentials (because it needs to be
updated to use the new v2 endpoint).
see: #5877
see: #5876
see: #5805
