Move services/shell to services/service_manager

services/shell/manifest.json

-{
-  "manifest_version": 1,
-  "name": "service:shell",
-  "display_name": "Service Manager",
-  "capabilities": {
-    // NOTE: This manifest is for documentation purposes only. Relevant
-    // capability spec is defined inline in the ServiceManager implementation.
-    //
-    // TODO(rockot): Fix this. We can bake this file into ServiceManager at
-    // build time or something. Same with service:catalog.
-    "provided": {
-      // Clients requesting this class are able to connect to other clients as
-      // specific users other than their own.
-      "shell:user_id": [ ],
-      // Clients requesting this class are allowed to register clients for
-      // processes they launch themselves.
-      "shell:client_process": [ ],
-      // Clients requesting this class are allowed to connect to other clients
-      // in specific process instance groups.
-      "shell:instance_name": [ ],
-      // Clients requesting this class are run as a unique user id which is
-      // visible to clients run as any user.
-      "shell:all_users": [ ],
-      "shell:block_wildcard":  [ ],
-      // Clients requesting this class block inbound requests to bind interfaces
-      // from other sources who specify wildcard rules in their manifest
-      // capability interface sets.
-      "shell:explicit_class": [ ],
-
-      "shell:service_manager": [ "shell::mojom::ServiceManager" ]
-    },
-    "required": {
-      "service:shell": [ "shell:all_users" ]
-    }
-  }
-}