anvi-server version should be seen somewhere

[meren]

Hi,

I think this could be a nice place for it, but they can be tiny:

But we need to show both anvio version, and users db version. I made some changes (5a56e6d4353ce4cf0359b048ea6317f3aa0ae3ca), so both can be obtained easily via these two variables:

anvio.__version__
anvio.__users_db_version__

Thanks in advance, Tobi!

[paczian]

addressed in #321