Switch the matrix hosts secret management from colmena to sops-nix

.sops.yaml

@@ -12,6 +12,7 @@ keys:
   - &admin_gpg_dante 3D70F61E07F64EC4E4EF417BEFCD9D20F58784EF
   - &host_age_git age18zaq9xg9nhqyl8g7mvrqhsx4qstay5l9cekq2g80vx4920pswdfqpeafd7
   - &host_age_forgejo_actions_runner age10xz2l7ghul7023awcydf4q3wurmszy2tafnadlarj0tvm7kl033sjw5f8t
+  - &host_age_matrix age1f7ams0n2zy994pzt0u30h8tex6xdcernj59t4d70z4kjsyzrr3wsy87xzk
 creation_rules:
   - path_regex: config/hosts/git/.*
     key_groups:
@@ -45,6 +46,22 @@ creation_rules:
           - *admin_gpg_dante
         age:
           - *host_age_forgejo_actions_runner
+  - path_regex: config/hosts/matrix/.*
+    key_groups:
+      - pgp:
+          - *admin_gpg_djerun
+          - *admin_gpg_stb
+          - *admin_gpg_jtbx
+          - *admin_gpg_yuri
+          - *admin_gpg_june
+          - *admin_gpg_haegar
+          - *admin_gpg_dario
+          - *admin_gpg_echtnurich
+          - *admin_gpg_max
+          - *admin_gpg_c6ristian
+          - *admin_gpg_dante
+        age:
+          - *host_age_matrix
   - key_groups:
       - pgp:
           - *admin_gpg_djerun