PERF: Memoize core svgs in memory to avoid expensive XML parsing. (PR #13221)

The XML parsing of SVGs is done whenever the cache expires or on the first load after a reboot. In one of our production instance, parsing ranges from 30ms to 70ms which is not ideal. Instead, we’ve decided to make a small memory trade off here by memoizing the core SVGs once on boot to avoid parsing of the SVG files during the duration of a request. The memozied hash will take up 57440 bytes or 0.05744 megabytes in size.


@ZogStriP Thank you for the review :+1: