chore: 🤖 add no hosts message if no hosts availabl

ui/core/app/templates/scopes/scope/projects/project/host-catalogs/host-catalog/host-sets/host-set/hosts.hbs

@@ -1,7 +1,23 @@
-<Form::HostSet::Hosts
-  @model={{@model.hostSet}}
-  @hosts={{@model.hosts}}
-  @submit={{route-action "save" @model.hostSet}}
-  @cancel={{route-action "cancel" @model.hostSet}}
-  @toggleHost={{route-action "toggleHost" @model.hostSet}}
-/>
+{{#if @model.hosts}}
+  <Form::HostSet::Hosts
+    @model={{@model.hostSet}}
+    @hosts={{@model.hosts}}
+    @submit={{route-action "save" @model.hostSet}}
+    @cancel={{route-action "cancel" @model.hostSet}}
+    @toggleHost={{route-action "toggleHost" @model.hostSet}}
+  />
+{{/if}}
+
+{{#unless @model.hosts}}
+  <Rose::Layout::Centered>
+    <Rose::Message @title={{t "titles.no-host-set-hosts"}} as |message|>
+      <message.description>
+        {{t "descriptions.no-host-set-hosts"}}
+      </message.description>
+      <message.link @route="scopes.scope.projects.project.host-catalogs.host-catalog.hosts.new">
+        <Rose::Icon @name="plus-circle-outline" />
+        {{t "titles.new"}}
+      </message.link>
+    </Rose::Message>
+  </Rose::Layout::Centered>
+{{/unless}}

ui/core/translations/en-us.yaml

@@ -86,6 +86,7 @@ titles:
   hosts: Hosts
   targets: Targets
   global: Global
+  no-host-set-hosts: No Hosts Available
 descriptions:
   host-catalogs: Overview of collections of hosts and host sets.
   empty-set: There are no items to display yet.  You may be able to add items or try back later.
@@ -98,6 +99,7 @@ descriptions:
   groups-welcome: Groups are collections of users.
   auth-methods-welcome: Auth methods are configurations to authenticate users.
   targets-welcome: Targets provide Users the means to connect to and interact networked services. A Target contains a collection of Hosts and a collection of Credentials.
+  no-host-set-hosts: Before associating hosts with this host set, create hosts within the host catalog.
 states:
   info: Info
   success: Success