Add an option to disable encryption in new chats

Right now NeoChat (or more technically, libQuotient) decides to use
encryption by default in new chats. Some users may not prefer or need
this, so a new option is added under Security to change this behavior.

BUG: 498375

src/neochatconfig.kcfg

@@ -223,6 +223,10 @@
       <label>Reject unknown invites</label>
       <default>false</default>
     </entry>
+    <entry name="PreferUsingEncryption" type="bool">
+      <label>Prefer encrypting chats</label>
+      <default>true</default>
+    </entry>
   </group>
 </kcfg>
 

src/neochatconnection.cpp

@@ -145,6 +145,10 @@ void NeoChatConnection::connectSignals()
             });
         },
         Qt::SingleShotConnection);
+    setDirectChatEncryptionDefault(NeoChatConfig::preferUsingEncryption());
+    connect(NeoChatConfig::self(), &NeoChatConfig::PreferUsingEncryptionChanged, this, [] {
+        setDirectChatEncryptionDefault(NeoChatConfig::preferUsingEncryption());
+    });
 }
 
 int NeoChatConnection::badgeNotificationCount() const

src/settings/NeoChatSecurityPage.qml

@@ -65,6 +65,21 @@ FormCard.FormCardPage {
                 NeoChatConfig.save();
             }
         }
+        FormCard.FormDelegateSeparator {
+            above: rejectInvitationsDelegate
+            below: preferEncryptionDelegate
+        }
+        FormCard.FormCheckDelegate {
+            id: preferEncryptionDelegate
+            text: i18nc("@option:check", "Turn on encryption in new chats")
+            description: i18nc("@info", "If enabled, NeoChat will use encryption when starting new direct messages.")
+            checked: NeoChatConfig.preferUsingEncryption
+            enabled: !NeoChatConfig.preferUsingEncryptionImmutable
+            onToggled: {
+                NeoChatConfig.preferUsingEncryption = checked;
+                NeoChatConfig.save();
+            }
+        }
     }
     FormCard.FormHeader {
         title: i18nc("@title:group", "Encryption")