aarch64 support

[ctron]

Ideally Drogue Cloud should be buildable and runnable on an pure aarch64 (armv7) environment. Currently there are a few obstacles. This is a tracking issue:

• [x] Need to build and publishaarch64 build container: Build containers are published for amd64 and aarch64 now
• [x] Ensure Drogue Cloud builds in aarch64
• [ ] Build and publish aarch64 images during the release
• [ ] Test aarch64 when releasing
• [ ] Run Drogue Cloud on aarch64 (should work, untested)
• [ ] Run dependencies on aarch64
  • [x] Strimzi (requires an update to 0.27, can be done when deploying)
  • [ ] Knative (only for the example) – https://github.com/knative-sandbox/eventing-kafka-broker/issues/1908
  • [ ] Keycloak – Requires the operator and Keycloak
  • Tracking issue: https://github.com/keycloak/keycloak/issues/8825
  • Alternative: https://hub.docker.com/r/sleighzy/keycloak
  • Operator can be built using:

    podman build --from "docker.io/library/golang:1.17"