Output some useful information when running the rails console

What does this MR do?

When running the Rails console (in development or production) it is helpful to have some status information shown, such as the Gitlab version and database version.

Example of new output:

| => rails c
-------------------------------------------------------------------------------------
 Gitlab:       10.8.0-pre (c7c9f38d019)
 Gitlab Shell: 7.1.2
 postgresql:   9.5.11
-------------------------------------------------------------------------------------
Loading development environment (Rails 4.2.10)
[1] pry(main)> 

Additional information will be added to Geo installations (showing whether Geo is enabled and if the server is a primary or secondary server).

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

It's useful to seem some information, particularly for a sysadmin who might be running multiple consoles.

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• [-] Documentation created/updated
• [-] API support added
• [-] Tests added for this feature/bug
• Review
  • [-] Has been reviewed by UX
  • [-] Has been reviewed by Frontend
  • Has been reviewed by Backend
  • [-] Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• [-] Internationalization required/considered
• End-to-end tests pass (package-and-qa manual pipeline job)