feat: Noir subrepo. (#3369)

Finally.

Builds the now subrepo'd noir repository. At present this just builds
nargo for x86 and arm, meaning our sandbox install script can now
provide a wrapper `aztec-nargo` that is guaranteed to always be exactly
what we want, regardless of any modifications to macros, compilers,
packages, or whatever. Decouples aztec from being dependent on Noirs
deployment pipeline, while still providing the ability to push changes
back to Noir.

Still need to do work to build npm packages and portal them into
yarn-project. Will do in separate PR.

* Removes old benchmarking stuff and commented canary stuff from
pipeline.
* Adds nargo x86 and arm builds, outputing a multiarch image that also
runs efficiently on macs.
* Removes a load of ARCH specific hack stuff in build-system, in favour
of all cache image URI's now just have their arch appended to their tag.
The arch is determined by the arch of the build system. This required a
small "hack(?)" whereby we will fall back from an unfound arch (arm) to
x86, as we build some of our arm images from previously build x86
images, but i anticipate that'll change at some point.
* Remove some project scripts that bleed the build-system abstraction
(e.g. deploy_docker.sh).
* Introduces `[ci dry-deploy]` commit message command for doing dry run
of deploys. We no longer have conditional workflow filters for
deployment to enable this. I.e. there is always deploy jobs, they just
noop out asap. If dry-deploy is enabled, the deploy jobs will run to
"completion" but doesn't actually execute pushes to dockerhub, and just
runs `npm publish` in dry-run mode.
* Gets rid of `VERSION` files and the sanity check is it got in the way
of the above, and I don't even remember why it was there.
* `build-system` can now launch arm spot instances. This can be
requested e.g. `cond_spot_run_build noir 32 arm64`.
* Added a script to help bootstrap build-instances in case we need to
create new AMI's again in future (I had to create and arm one).
* Deleted some build-system scripts I couldn't see used anywhere.
* `deploy_dockerhub` script now takes list of arches and does the
manifest generation itself.
* Introduces a `should_deploy` script which enables the early out of
deployment jobs. At present this causes exit if there is no COMMIT_TAG.
In future it'll want to run the deploy steps if BRANCH is master as
well.


Follow up PRs will:
* Build NPM packages and portal them into yarn-project.
* Modify sandbox install script to pull noir image, install
`aztec-nargo` wrapper.
* Update vscode plugin to allow selection between global `nargo` or
`aztec-nargo` if both found.
* Someone will do some magic to use the nargo container in github
codespaces so users can press `.` and play.

Author: charlielye

.circleci/config.yml

@@ -1 +1 @@
-aztec3-packages
+aztec