Remove remaining deprecated contributed commands.

Moving them to homebrew-boneyard.

Closes #28657.
Move SCM wrappers from Contributions to ENV/scm.

Closes #32615.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
Added pixbuf cache update to install to properly update loader.cache
librsvg: update 2.36.3 bottle.