Updates container build tooling

[c-kruse]

Resolves Issue https://github.com/skupperproject/skupper/issues/1742

• Includes labels on container images suggested in OCI spec
• Container image executables built with without CGO for consistency
• All executables built with ldflags "-s -w" by default
• Make targets updated
  • Uses pattern rules for container image targets
  • Uses variables REGISTRY+IMAGE_TAG instead of individual per-image variables like CONTROLLER_IMAGE.
  • docker-build now a plain-ole' docker build for the host platform - mostly for development use
  • multiarch-oci now does multiarch builds with output type of oci-archive (tar files in ./oci-archives).
  • push-multiarch-oci uses skopeo to push oci archives to registry
  • (docker|podman)-load-oci conveneince method to load images from multiarch-oci archives to local image storage
  • describe-multiarch-oci prints fully qualified images repo:tag@sha256 for the image index and individual platforms
  • cleans up old package+release targets
• CircleCI config cleanup unused targets and rework jobs for updated container build targets.
• Dropped some platforms from the skupper cli builds: linux-i386, linux-arm32 and windows-i386. No real solid numbers behind this, but didn't feel they were likely to be used and they were contributing to the build step taking a long time.

[c-kruse]

Hoping to rebase this on the config-sync -> kube-adaptor rename before marking as ready for review.

Throws out lots of ideas that I thought were sensible. I'd appreciate the team's thoughts.

Also have a reference integration test (not planned to merge) open here https://github.com/skupperproject/skupper/pull/1768 to attempt to proof out the idea of the container build -> oci archive -> load in tests -> publish flow. Example circleci run

[c-kruse]

For anyone interested in inspecting the images themselves

$ make describe-multiarch-oci push-multiarch-oci REGISTRY=quay.io/ckruse IMAGE_TAG=$(git rev-parse --short HEAD)
index:
  - quay.io/ckruse/bootstrap:1f7e2f12@sha256:3e94c19c83336e1a22d2c415c43a4b9932b96815a9980b0ffafcdf3384048d79
  - quay.io/ckruse/config-sync:1f7e2f12@sha256:96c1b4fd316025a6348b16ca833d06a31b01a86b3a66bc1d0522ced133783a0e
  - quay.io/ckruse/controller:1f7e2f12@sha256:d09fddc9accf447570893283c8650376a75b7f598061c56dd652811b5d903cf5
  - quay.io/ckruse/network-console-collector:1f7e2f12@sha256:8a171c7a35510889217d38d6a909a670f661cf06f80d4ab0b915fdfc47a7a4d6
amd64:
  - quay.io/ckruse/bootstrap:1f7e2f12@sha256:3334fc4d3333ecb53cbe2df4172bdf8d332869b818c7e60be6e75fcfd4fdab04
  - quay.io/ckruse/config-sync:1f7e2f12@sha256:007f2d8e368a7958f678f111febf7b0753ea02b591730a20bfdf51f8a9747440
  - quay.io/ckruse/controller:1f7e2f12@sha256:c36983cafc8618b07b5d7da4cc8d199f63cee71a093c01ba29a8e3ad4313bcfd
  - quay.io/ckruse/network-console-collector:1f7e2f12@sha256:2cb26080a642ba945c43b49797423ea804e0bea76cf3dc06dd5288609ff3aa6f
arm64:
  - quay.io/ckruse/bootstrap:1f7e2f12@sha256:74006ee179d46733d38dfa9cd2600a3dd7cffa6686389b5f2d3d5008820c340e
  - quay.io/ckruse/config-sync:1f7e2f12@sha256:18e366f75cd51d7793dfcee29e84b1ebd977165a7a71c4068bd8823f8f49be6f
  - quay.io/ckruse/controller:1f7e2f12@sha256:e8d0bcdb7b2bca9a917801faeddde585fb3bd9fe235783f83ce3979ef6fb9c72
  - quay.io/ckruse/network-console-collector:1f7e2f12@sha256:973f5a562f2102225be9499b7fcf0e18230698217ac3f06924dd9d87e9f9edde
skopeo copy --all \
        oci-archive:oci-archives/bootstrap.tar \
        "docker://quay.io/ckruse/bootstrap:1f7e2f12"
....