Add cross-platform docker builds

[mh013370]

Q	A
Bug fix?	no
New feature?	yes
API breaks?	no
Deprecations?	no
Related tickets	fixes #207
License	Apache 2.0

What's in this PR?

PR #205 made cross-platform docker image builds possible. This PR makes the nifikop docker image published cross-platform following the below docs:

• https://www.docker.com/blog/faster-multi-platform-builds-dockerfile-cross-compilation-guide/
• https://sdk.operatorframework.io/docs/advanced-topics/multi-arch/#manifest-lists

Why?

To enable running nifikop on multiple architectures.

Checklist

• [x] Implementation tested
• [x] Error handling code meets the guideline
• [x] Logging code meets the guideline
• [x] User guide and development docs updated (if needed)
• [x] Append changelog with changes

[mh013370]

@juldrixx Please hold on merging this. I've just noticed that we are no longer generating manifests prior to building the image with this change.

[mh013370]

Okay this is good to go. I re-verified that cross-platform images are built :)

[juldrixx]

The build failed after the merged see