Allow user configuration

[yankovs]

Hey! :)

Recently one of our guys wanted to query a sample that was 2.5mb and he's got the visitor profile option and this failed because of the 1mb limit. In general, it could be nice to have a way to configure these kinds of hardcoded values, what do you think?

[danielplohmann]

Hey!

Yeah, I think it makes sense to extend this in a way that an administrator can fully configure roles and permissions in a more fine-grained way as currently suggested with visitor/contributor. I didn't get around implementing this properly, but want to do this in the future, when I also start moving the front-end to use actual object abstraction for DB interactions, which should simplify things. But first, jobs/queue management need to be addressed a bit more. :)