Add integration test classes for the CLI user plugin
Add integration tests for joingroup and leavegroup subcommands
Add integration tests for user list subcommand
Simplify testList integration test
Add integration test for user add subcommand
Decorate failing tests with pytest.mark.xfail decorator
Add integration tests for the user add subcommand

- Test various experimenter input (middlename, email, institution, admin)
- Test various group assignment signatures
- Test various password options
Fix testList integration test with --sort-by-email option
Add integration test for email subcommand
Add integration tests for user password subcommand
Add extra login step to check password tests
Remove py.mark.xfail decorators (see #11687)
Merge pull request #1782 from sbesson/clitest_user

Add integration tests for the CLI user plugin