Improve FAQ page

[roji]

• 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...