Use only the page relevant pieces in the parser cache key. Eg. two users with differe...

Use only the page relevant pieces in the parser cache key. Eg. two users with different math options will now
use the same parsercache entry for articles without <math> tags.
The cache key format is kept as a fallback so the old cached entries can be reused.

Should boost parsercache hits, but it also makes easier to pollute the parsercache by tag hooks that behave
badly, directly using $wgUser or $wgLang.

Extensions hooking PageRenderingHash now see !edit=0 and the !printable=1 bits.

Fixes bug 24714 - Usage of {{#dateformat: }} in wikis without $wgUseDynamicDates can lead to unexpected results

Builds upon r70498, r70498, r70501, r70517, r70651, r70653, r70765, r70780.