feat(shield): migrate feature keys to host-shield.yaml

[aroberts87]

As the host-shield.yaml file has introduced new keys, we are now able to migrate those feature settings from the legacy dragent.yaml file to the new format.

This change also takes the opportunity to clean up a few areas around related helper function use where relevant.

What this PR does / why we need it:

Checklist

• [x] Title of the PR starts with type and scope, (e.g. feat(agent,node-analyzer,sysdig-deploy):)
• [x] Chart Version bumped for the respective charts
• [x] Variables are documented in the README.md (or README.tpl in some charts)
• [x] Check GithubAction checks (like lint) to avoid merge-check stoppers
• [x] All test files are added in the tests folder of their respective chart and have a "_test" suffix