Don't expand templates inside topic titles

Topic titles, such as '{{ok}}' when passed into an i18n message as
a parameter get expanded.  Prevent this by using Message::rawParams
along with htmlspecialchars. In most cases this was already working
fine, but post history and topic history pages were incorrectly
expanding it inside the html <title> and the page header.

This additionally fixes a double escaping issue where <foo> inside
a topic title would render as `&lt;foo&gt;`

Bug: 65143
Change-Id: I27ac641196ebca84f92b10ca55b89f87753b0911
Merge "Don't expand templates inside topic titles"