Add interaction to admin:user:create command

[cmuench]

Description

Add interaction to "admin:user:create" command. This is more convenient and user friendly.
The interaction is done by Symfony Question helper. This is a default class of the Symfony Console component.
If a required option is not passed, the command will ask for the input value. The password is validated against the standard user password validator.

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[cmuench]

@vkublytskyi I'm not sure why the integration test failed. It got a timeout. Maybe a travis problem?

[vkublytskyi]

@cmuench I restarted the job. Issue with Travis failures by timeout should e fixed in #11555.

[davidalger]

I restarted that job twice already…seems the 3rd time is a charm apparently :)

Very nice work @cmuench!

[cmuench]

Thanks.