Mattermost Operator: Istio mTLS STRICT

Package Merge Request

Package Changes

Adds a default PeerAuthentication for Mattermost Operator, set to strict.

As usual can be set to the old behavior with:

addons:
  mattermostoperator:
    values:
      istio:
        mtls:
          mode: PERMISSIVE

Package MR

https://repo1.dso.mil/platform-one/big-bang/apps/collaboration-tools/mattermost-operator/-/merge_requests/38

For Issue

Closes https://repo1.dso.mil/platform-one/big-bang/bigbang/-/issues/1051