Improve FAQ page

* Some of the answers are no longer relevant in their current form (e.g. stored procedure vs. function)
* The layout sucks with the huge titles, make them shorter etc.
 
Frequent missing questions:

* TimeoutException
* My cloud provider closes my idle connections (answer: turn on keepailve)

/cc @NinoFloris @vonzshik @Brar for any other candidates...