Remove special placement `Q` in prize pools

[mbergen]

fwiw, there seems to be only ~10-15 pages using this (on CS). Maybe we can talk to them to get rid of it.
Search queries: hastemplate:Slot insource:"q=true" and hastemplate:prize_pool_slot insource:"place=q"

Originally posted by @mbergen in #7821

[hjpalpha]

there might be some with |q=1 etc instead of true

[mbergen]

there might be some with |q=1 etc instead of true

Searching with hastemplate:Slot insource:/\|q=/ produced the same 3 pages the rough query produced