[svg] Relocate out of experimental

Move the SVG rendering code to modules/svg, and componentize.
Also split into include/src/utils.

As external clients still reference the old header locations,
introduce temporary forwarding headers to facilitate the migration.

Change-Id: Ib289dbdcd80c16a01c47805e7242f2e08bebc165
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/326948
Reviewed-by: Tyler Denniston <tdenniston@google.com>
Commit-Queue: Florin Malita <fmalita@google.com>
100 files changed