Realize searching group with tag

[triszt4n]

Idea:

In groups menu, user should be able to search groups containing the tag from a newly implemented search bar. (copy search bar from here: https://bulma.io/documentation/components/panel/) See issue #230 before this one.

Reason:

Migth be useful for finding study mates.

[OmTheTurtle]

I was thinking about this lately. I think it could be great if people could search for group name (and description) too. and I see two way of implementing searching:

• Dedicated input fields for name, tags and description.
• One unified input field with possibly using fuzzy search

If we want fuzzy search, looking at Objection.js' documentation, we can't use pagination.

On the front-end, I think it's inevitable to perform hard reload when the user hits the search button, mainly because we use pagination and server-rendered HTML (or at least it looks like it'd need significant front-end JS code to implement it the right way).

Either way we'll definitely need to create indices in the fields we want to search for in groups table.

Additionally, having a date range picker makes a lot of sense, since people probably don't want to see very old groups.
(More additionally, having a room selector makes sense too, but we can make a dedicated page for this that's available from the main page.)