[ER]: Allow finding of a User Object using trust_id

[DanDavies2]

Description

It is quite hard to maintain a consistent naming convention in an environment if you have more than 1 administrator, some automated systems etc

For example you might have John Smith, John.Smith, john.smith in the name field with different cases and the same applies to the login field too

Often the only consistent field on a User is the trust_id but there is not currently a way to initialise a User Object by specifying the trust_id

In most cases this trust_id will be coming from Azure AD or similar and will therefore always be consistent with a consistent case structure too

If possible could we have the ability to initialise a User object in the following way

fetch_user = User(connection=conn, trust_id='John.Smith@test.com')

This would save us having to try and fetch a user in multiple ways and/or use the list_users method and then loop through them all checking for a match