Add EntityHandler::makeParserOptions

WikiPage calls out to this in order to get a ParserOptions
object for use in WikiPage::doEditUpdates. We need to override
it, as we need custom options in there.

Bug: 60715
Change-Id: I2541d384fe424190db2514295bfe751961adfa95
(cherry picked from commit 9a8d76d733a2600955a0450c092c5bb1d57a4f15)