Add feature flag for reply in thread

Currently the ability to reply in threads was added but not the ability to actually view threads so this doesn't currently make much sense to just have enabled int he main build.

Note: I want to cherrypick this so it's just the flag. I'll add a feature flag page to dev tools for master soon.

src/neochatconfig.kcfg

@@ -152,5 +152,11 @@
       <default></default>
     </entry>
   </group>
+  <group name="FeatureFlags">
+    <entry name="Threads" type="bool">
+      <label>Enable threads</label>
+      <default>false</default>
+    </entry>
+  </group>
 </kcfg>
 

src/qml/HoverActions.qml

@@ -7,6 +7,7 @@ import QtQuick.Layouts
 
 import org.kde.kirigami as Kirigami
 import org.kde.neochat
+import org.kde.neochat.config
 
 /**
  * @brief A component that provides a set of actions when a message is hovered in the timeline.
@@ -108,7 +109,7 @@ QQC2.Control {
                     }
                 },
                 Kirigami.Action {
-                    visible: !root.currentRoom.readOnly
+                    visible: Config.threads && !root.currentRoom.readOnly
                     text: i18n("Reply in Thread")
                     icon.name: "dialog-messages"
                     onTriggered: {