Make transcluded special pages not disable cache in miser mode.

Make transcluded special pages not disable cache in miser mode.

Previously {{Special:Foo}} would cause parser cache to be disabled,
now have a method in SpecialPage to control this behaviour and set
arbitrary caching times.

Note: This does not affect caching of direct views to the special page

The new default is now disabling cache if not in miser mode,
otherwise setting to 1 hour, except for Special:Recentchanges
and Special:Newpages which set to 5 minutes. These values are
possibly really low, but for now I think best to be close to the
old behaviour. We had 0 caching for these things for years, and
afaik it hasn't caused any big issues. Part of me wonders if
Special:Recentchanges should stay at 0, but that sounds crazy.

This change also causes transcluded special pages to not be
"per-user" if they are being cached (Specificly $wgUser et al
become 127.0.0.1).

Bug: 60561
Change-Id: Id9ce987adeaa69d886eb1c5cd74c01072583e84d