use jtbx SSH key instead of PGP key and use SOPS merge for admin keys

Use jtbx SSH key instead of his PGP key and re-organize .sops.yaml
around the SOPS merge feature to accommodate admin age/SSH keys.

renovate.json

@@ -38,13 +38,10 @@
         "!git.hamburg.ccc.de/ccchh/oci-images/keycloak"
       ]
     },
-    // Automatically merge patch level updates
-    // https://docs.renovatebot.com/key-concepts/automerge/
     {
       "matchUpdateTypes": ["patch"],
-      "automerge": true,
-      "ignoreTests": true,
-      "automergeType": "branch"
+      "matchCurrentVersion": "!/^0/",
+      "automerge": true
     },
     {
       "matchDatasources": ["docker"],