archbuild: Add systemd conf for devtools resource control

Leveraging devtools 1.0.4, install systemd snippets which

• distribute CPU and IO equally between users,
• distribute CPU and IO equally between build containers of a user,
• prefer distributing CPU and IO to things that are not build containers, and
• copy our user oomd config for users to apply to build containers.

This depends on devtools!172 (merged) (cc @anthraxx).

For IO distribution to actually work we might need to set bfq as the scheduler, but I'm not sure.

added 2 commits

• 378a7b4f - 1 commit from branch master
• 0b3e2534 - archbuild: Add systemd conf for devtools resource control

Compare with previous version

enabled an automatic merge when the pipeline for 0b3e2534 succeeds

mentioned in commit f8d85a5c

merged