feat(shield): Allow configurable DNS Policy for Host Shield

[aroberts87]

What this PR does / why we need it:

SSIA

Checklist

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

[francesco-furlan]

LGTM
just one small thing around the "default" function I recall we had issues in the past, but maybe it was related to some old helm versions that we don't support anymore