post https://api.codepipes.io/identity/v0/organizations//creds/assignscope
Assign a credentail to an entity so that the entity may use the credential within the set scopes.
If the cred is already assigned with a different scope, this appends the new scope.
There could only be one assignment for one scope type.
CredScopes which aren't allowed for a credType will result in error (allowed scopes can be verified through meta API or the cred list API)