Search update

Fix #1385

See my comments on the above issue, this
a) removes simple search on/off option from ACP
b) updates search to use JS to toggle the basic / advanced panels (remembers choice via minmax)
c) updates PM search as b
d) without JS enabled the user will only see the advanced options 
e) guest will see the advanced by default but can collapse it (should this maybe be collapsed by default instead?)