Cache regex instances in most cases (#27699)

Cache regex instances in most cases (#27699)

Using static Regex functions that take in a pattern is bad because the pattern constantly needs to be re-parsed. With https://github.com/space-wizards/RobustToolbox/pull/5107, the engine has an analyzer to warn for this practice now.

This commit brings most of content up to snuff already, though some of the tricker code I left for somebody else.