Users admin tables improvments

First commit  is to change default order of users to something useful: proposed to see last registered users. (before you see alphabetical order, and if you have more then 20 users it really usefulness). This change safe 2 clicks at all :-)

Second commit is to see more information in pending registrations table. Important one is "Registration date". It is missing now, and is needed to make decision about the user.

| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | no
| License       | MIT
| Doc PR        |  no