Jenkins Reorganization

[tianon]

This is an FYI / heads-up that I plan to reorganize and move our "new build system" Jenkins jobs Soon™

Right now, they're all under the "work-in-progress" folder (they've been there for over a year) and now, since #93, all the images have moved over, so we're very overdue for restructuring these.

I think #91 is the only actively in-progress thing that would really be affected by this, but if @yosifkit doesn't get it to a state he's happy with before I start executing on this, I'll happily help with any rebase fallout. 🙇 ❤️

Current/before:

multiarch/ARCH/REPO (old, disabled)

wip/new/meta
wip/new/trigger-gha
wip/new/trigger-ARCH
wip/new/build-ARCH
wip/new/deploy-ARCH

Plan/after: ("the meta build system")

multiarch/ARCH/REPO (old, disabled, could be removed)

meta/meta
meta/ARCH/trigger
meta/ARCH/build
meta/ARCH/deploy

Notably, this will be axing the notion of "GHA" as an explicit architecture; @yosifkit came up with having the meta/amd64/trigger, etc jobs do the per-architecture GHA triggering and there's just no meta/amd64/build job (for now) -- this has a lot of benefits, including being able to choose GHA vs non-GHA per-build, etc. This is also easier to accomplish thanks to #92. 😄

This also relates heavily to docker-library/faq#39 (and is honestly a prerequisite IMO).

[tianon]

I also plan to add flat, triggers, builds, and deploys as "views" within Jenkins to make browsing the result easier depending on which bit of data we're looking for (which should all be really easy to maintain since they'll be name-based views that don't need to be updated as architectures come and go in the future).