Load configuration from disk

- Add FileIO backend
- Fill login form with saved configuration

src/Gui/Settings/Settings.qml

@@ -0,0 +1,39 @@
+pragma Singleton
+
+import QtQuick
+import QtCore
+
+import QSpec
+
+QtObject {
+  property string configDir: StandardPaths.writableLocation(StandardPaths.AppConfigLocation)
+  property string dataDir: StandardPaths.writableLocation(StandardPaths.AppDataLocation)
+
+  property var _json
+
+  function load() {
+    if (FileIO.exists(configDir) === false)
+      FileIO.mkpath(configDir)
+
+    if (FileIO.exists(dataDir) === false)
+      FileIO.mkpath(dataDir)
+
+    try {
+      _json = JSON.parse(FileIO.read(`${configDir}/config.json`))
+    } catch (_) {
+      print(`Failed to read ${configDir}/config.json`)
+      return false
+    }
+
+    if (_json)
+      return true
+
+    print(`Empty or invalid configuration at ${configDir}/config.json`)
+    return false
+  }
+
+  function save() {
+    print(`Saving settings to ${configDir}/config.json`)
+    FileIO.write(`${configDir}/config.json`, JSON.stringify(_json))
+  }
+}