Autofill required attributes on block insertion

[malud]

Some blocks have required attributes. We could insert them directly while completing the block suggestion.

Block	Attribute
file	document_root
spa	bootstrap_file, paths
openapi	file
oauth2	grant_type, token_endpoint, client_id, client_secret
beta_oauth2	grant_type, authorization_endpoint, token_endpoint, client_id, client_secret
oidc	configuration_url, client_id, client_secret, verifier_value
jwt_signing_profile	signature_algorithm
saml	idp_metadata_file, sp_acs_url, sp_entity_id