New component proposal: Admin site

[anorsich]

Pretty much in every project, there is some kind of admin routine. There are some key things, which are required pretty much by any product:

1. Users listing. As an admin, I can see who signed up along with some key user activities/metrics.
2. Shadow login into the user account. As an admin, I would like to be able to login into a user account to troubleshoot any kind of support issues.
3. Company listing. Probably optional, but pretty much any SaaS has companies.

I think we can take some core admin functionality from one of our products.

[anorsich]

@umitskevich Can we take this component out of your last project? In a first version, I propose to start from a simple user listing and shadow login feature.