Complete refactor of Browser Integration classes

* Removed option to attach KeePassXC to the browser extension. Users must use the proxy application to communicate with KeePassXC.
* Significantly streamlined proxy code. Used same implementation of stdin/stdout interface across all platforms.
* Moved browser service entry point to BrowserService class instead of NativeMessagingHost. BrowserService now coordinates the communication to/from clients.
* Moved settings page definition out of MainWindow
* Decoupled BrowserService from DatabaseTabWidget
* Reduced complexity of various functions and cleaned the ABI (public vs private).
* Eliminated BrowserClients class, moved functionality into the BrowserService
* Renamed HostInstaller to NativeMessageInstaller and renamed NativeMessageHost to BrowserHost.
* Recognize XDG_CONFIG_HOME when installing native message file on Linux. Fix #4121 and fix #4123.

src/browser/CMakeLists.txt

@@ -20,15 +20,15 @@ if(WITH_XC_BROWSER)
     set(keepassxcbrowser_SOURCES
             BrowserAccessControlDialog.cpp
             BrowserAction.cpp
-            BrowserClients.cpp
             BrowserEntryConfig.cpp
             BrowserEntrySaveDialog.cpp
-            BrowserOptionDialog.cpp
+            BrowserHost.cpp
+            BrowserSettingsPage.cpp
+            BrowserSettingsWidget.cpp
             BrowserService.cpp
             BrowserSettings.cpp
-            HostInstaller.cpp
-            NativeMessagingBase.cpp
-            NativeMessagingHost.cpp
+            BrowserShared.cpp
+            NativeMessageInstaller.cpp
             Variant.cpp)
 
     add_library(keepassxcbrowser STATIC ${keepassxcbrowser_SOURCES})