Display domainrole integrator for domain

It's better to display all domain roles.

Change-Id: I70915993016fb1c9feec1016cb78c1892e6c15c3
Fixes: #1961
Remove useless code about UserParty when importing scm data

In fact, we can get user party from their email, for example, we know he is from
"Intel" if his email ends with "intel.com", so it's useless to maintain UserParty

Change-Id: I54f5afb46e54573efd0616ebdd5fb42ade190c0d
Fixes: #1970
Fix user check logic.

User without email is allowed. However we can validate its email
format by EmailValidator.

Change-Id: Ic64243e0ade6f5ffd3398c43074a14d10bd36201