Migrate ejabberd uploads to mod_s3_upload and Garage

In addition to installing and configuring the new module, this also
enables public access to the S3 API via `bucket-name.s3.kosmos.org` as
well as Web access on `bucket-name.web.s3.kosmos.org` (when enabled).

Also includes some drive-by improvements to Chef attribute naming and
usage.

Co-authored-by: Greg Karékinian <greg@karekinian.com>

nodes/garage-2.json

@@ -23,7 +23,8 @@
       "kosmos_kvm::guest",
       "kosmos_garage",
       "kosmos_garage::default",
-      "kosmos_garage::firewall",
+      "kosmos_garage::firewall_rpc",
+      "kosmos_garage::firewall_apis",
       "apt::default",
       "timezone_iii::default",
       "timezone_iii::debian",
@@ -38,21 +39,20 @@
       "postfix::_attributes",
       "postfix::sasl_auth",
       "hostname::default",
-      "firewall::default",
-      "chef-sugar::default"
+      "firewall::default"
     ],
     "platform": "ubuntu",
     "platform_version": "20.04",
     "cloud": null,
     "chef_packages": {
       "chef": {
-        "version": "17.10.3",
-        "chef_root": "/opt/chef/embedded/lib/ruby/gems/3.0.0/gems/chef-17.10.3/lib",
+        "version": "18.3.0",
+        "chef_root": "/opt/chef/embedded/lib/ruby/gems/3.1.0/gems/chef-18.3.0/lib",
         "chef_effortless": null
       },
       "ohai": {
-        "version": "17.9.0",
-        "ohai_root": "/opt/chef/embedded/lib/ruby/gems/3.0.0/gems/ohai-17.9.0/lib/ohai"
+        "version": "18.1.4",
+        "ohai_root": "/opt/chef/embedded/lib/ruby/gems/3.1.0/gems/ohai-18.1.4/lib/ohai"
       }
     }
   },