Ability to set up proxy as an admin without user setting up the proxy first

Summary:

The current proxy functionality only seems to work if a user first allows someone to be their proxy. There should be a functionality as an admin to set this up without a user having to do something first.

Content (required):

As an application support employee I sometimes have to log in as another user in the test environment to check something and reproduce an issue to make a good analysis. Since we are using the chooser page in the testing environments at the moment we just reset the password and log in with the oracle credentials. But we want to force SSO for all environments and not just production. But this move will remove the option to log in as that user.