Admin: Make Teams page more useful

[olin256]

Namely:

• allow sorting by the columns
• include their registration / confirmation time in the columns
• don't do pagination

[krtko1]

Teams list view is probably last one which do not use new template. Sorting should be automatic with use of new template. Columns would need more thoughts which information should be included and which not. I think pagination is mandatory in new templates right now. That could be changed or we can set some larger value. By default if you are branch admin you would load all teams from that year which could be quite a lot. Some large value like 200 should be enough even for large venues I think.