Convert to AJAX DataTable content for accounts/by_host

[grutz]

When DataTables content get too big it takes too long for full results to process or appear on the screen. Overall tables SHOULD come from a RESTful-like source with limits and offsets.

Lets start with a typically overloaded t_accounts. accounts/by_host.json may take more than 3 minutes to return after loading 30,000+ records. This is probably because the query join is too much to handle..

https://github.com/KvasirSecurity/Kvasir/blob/master/controllers/accounts.py#L546

db(query).select(db.t_accounts.ALL, db.t_services.ALL, left=db.t_services.on(db.t_accounts.f_services_id==db.t_services.id))

Two things may help: first is AJAX with limit/offset, the second is a better query.