Sync Dockerfile and Dockerfile.cross and run as non-root user for 1.106

[mattray]

Backported #2166 for 1.106.1

What does this PR change?

• Successfully runs as non-root Sync Dockerfile and Dockerfile.cross and run as non-root user #2166

Does this PR relate to any other PRs?

• 1.106 shipped with a broken UI container (Opencost quick setup does not work #2144)
• Undoes the rollback (Remove non-root user to restore UI #2148)

How will this PR impact users?

• UI container won't run as root, works.

Does this PR address any GitHub or Zendesk issues?

• Closes OpenCost UI nginx should not run as root and should not run on a privileged port #2150 for the 1.106 branch

How was this PR tested?

• EKS (x86), Kind (Arm), K3s (Arm, x86), will retest with RCs before 1.106.1 release

Does this PR require changes to documentation?

• can finally publish release notes for 1.106 for OpenCost

Have you labeled this PR and its corresponding Issue as "next release" if it should be part of the next OpenCost release? If not, why not?

• We'll finally publish 1.106 because we have a working UI container.