Remove math specific code from ParserOptions

There is some math specific code in ParserOptions.
To allow extensions like math to change the cache key in a reasonable matter,
they need to get access to the information which options were used. Therefore,
optionUsed is public now and the additional argument $forOptions was added to
the PageRenderingHash hook.

Bug: 60234
Change-Id: Ieecb27216c39b7e6e354b4a1904fbff06506307d
Merge "Remove math specific code from ParserOptions"