Remove image wrappers

[michaelsauter]

With this change, images are not build in the cluster anymore. Instead, tasks use the prebuilt images on GitHub. In case of a private certificate, that is supplied via a secret volume to tasks.

Closes #621.

Tasks:

• Updated design documents in docs/design directory or not applicable
• Updated user-facing documentation in docs directory or not applicable
• Ran tests (e.g. make test) or not applicable
• Updated changelog or not applicable

[henrjk]

Regarding the current state that python builds are using pypi and configuring nexus as a trusted host in:

ods-pipeline/build/package/scripts/build-python.sh

Lines 65 to 66 in 1ddfe84

	pip3 config set global.trusted-host "${NEXUS_HOST}"
	pip3 config set global.extra-index-url https://pypi.org/simple

To my recollection the reason this was introduced was ultimately needed due to work around cases where the pypi json api is needed. This surfaced as described in issue:

• pip-compile does not provide all hashes when used against private nexus.
  #1412

Recently PR Generate hashes for all available candidates #1723 was merged and the PR for jazzband/pip-tools#1536 (comment) which is a duplicate of 1412 mentioned is still in progress. Once that can be merged it should enable the python build to only use the configured nexus for python builds and remove the fallback of pypi.

We could consider to revisit this when the above PR 1723 gets addressed.

Just adding that I also submitted the related Dev - Nexus RepoNEXUS-22828
Support PyPI JSON API

[henrjk]

LGTM

[michaelsauter]

@kuebler @gerardcl I'll merge this now in order to push new images into the registry. With those, I'll do a manual test run in our cluster. I expect a few issues here and there so maybe there will be a follow-up PR. Therefore I would appreciate your review & feedback, maybe you detect some other things in the PR that needs attention.

In general, we could be a bit more cautious before merging this, but I'll just make it as easy and fast as possible for myself to give this a spin outside tests.

If manual testing works out fine, I would create a new release soon.