Simplify container permissions

[sfowl]

Not ready for review yet, just testing changes on e2e tests. E2E tests look fine, ready for review.

[jeremychoi]

The changes look good to me. Meanwhile, while we are dealing with /home/rapidast, how about making changes to these locations where /home/rapidast is mentioned? (in fact these should have been modified previously, regardless of this PR so we can update separately though):

• rapidast/config/config-template-trivy-k8s-scan.yaml

  Line 43 in 20d4063

  inline: "trivy k8s --kubeconfig=/home/rapidast/.kube/config -n default pod --scanners=misconfig --report all --format json | convert_trivy_k8s_to_sarif.py"

• rapidast/helm/chart/templates/_helpers.tpl

  Line 48 in 20d4063

  # Otherwise, '/home/rapidast/.ZAP/policies/API-scan-minimal.policy' will be used by default.