[skottie] Cleanup: convert shape layer adapters to new pattern

Split off most shape layer components into own CUs (naming convention
following AE), and convert to new DiscardableAdapter pattern.

TBR=
Change-Id: Iba7800cff1998d3d7cf81dfd89b4193d02b59559
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/265147
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
27 files changed