Refactor user_files module & add live reloading

- Cleaner design for the backend user_files classes and simplified
  interaction with QML
- Config and theme files will now automatically reload when changed on
  disk
- Removed manual reload keybind and button

src/gui/PythonBridge/EventHandlers.qml

@@ -65,6 +65,19 @@ QtObject {
         py.showError(type, traceback, "", message)
     }
 
+    function onUserFileChanged(type, newData) {
+        if (type === "Theme") {
+            window.theme = Qt.createQmlObject(newData, window, "theme")
+            utils.theme  = window.theme
+            return
+        }
+
+        type === "Settings" ? window.settings = newData :
+        type === "UIState" ? window.uiState = newData :
+        type === "History" ? window.history = newData :
+        null
+    }
+
     function onModelItemSet(syncId, indexThen, indexNow, changedFields) {
         const model = ModelStore.get(syncId)
 

src/gui/PythonBridge/PythonBridge.qml

@@ -47,23 +47,9 @@ Python {
         call("BRIDGE.cancel_coro", [uuid])
     }
 
-    function saveConfig(backend_attribute, data, callback=null) {
-        if (! py.ready) { return }  // config not loaded yet
-        return callCoro(backend_attribute + ".write", [data], callback)
-    }
-
-    function loadSettings(callback=null) {
-        const func = "load_settings"
-
-        return callCoro(func, [], ([settings, uiState, history, theme]) => {
-            window.settings = settings
-            window.uiState  = uiState
-            window.history  = history
-            window.theme    = Qt.createQmlObject(theme, window, "theme")
-            utils.theme     = window.theme
-
-            if (callback) { callback(settings, uiState, theme) }
-        })
+    function saveConfig(backend_attribute, data) {
+        if (! py.ready) { return }  // config not done loading yet
+        callCoro(backend_attribute + ".set_data", [data])
     }
 
     function showError(type, traceback, sourceIndication="", message="") {

src/gui/PythonBridge/PythonRootBridge.qml

@@ -22,7 +22,13 @@ PythonBridge {
         addImportPath("qrc:/src")
 
         importNames("backend.qml_bridge", ["BRIDGE"], () => {
-            loadSettings(() => {
+            callCoro("get_settings", [], ([settings, state, hist, theme]) => {
+                window.settings = settings
+                window.uiState  = state
+                window.history  = hist
+                window.theme    = Qt.createQmlObject(theme, window, "theme")
+                utils.theme     = window.theme
+
                 callCoro("saved_accounts.any_saved", [], any => {
                     if (any) { callCoro("load_saved_accounts", []) }