Feature/basic app (#1)

Feature/Basic App (#1)

Basic App Structure Consists of Time Progress Dashboard, Time Progress Detail View and Time Progress Creator.
All of these have an AppDrawer with a Link To the Dashboard and all your Track Time Progresses, also an About Button.

Commits:
* Undetailed Commit more work
* Changed isEditing ? in Detail Screen and Extracted FAB row to widget
* Extracted Progress Detail Fab Row and Progress Detail select Date Btn to
widgets
* Create Progress Detail Widgets Folder
* Extracted Edit Dates Row Widget
* Extracted Functions from ui
* Made some fields private
* LoadTimerProgressList if unloaded function
* Created App Yes No Dialog Widget
* Using Yes No Dialog in Detail Screen
* Created TimeProgress Initial Default factory
* Renamed to Time Progress Tracker
* Added About Button in App Drawer
* Code cleanup
* Code clean up and fixed Bug with null as string in Repository

Signed-off-by Andreas Fahrecker <AndreasFahrecker@gmail.com>

lib/widgets/app_yes_no_dialog_widget.dart

@@ -0,0 +1,34 @@
+import 'package:flutter/material.dart';
+
+class AppYesNoDialog extends StatelessWidget {
+  final String titleText;
+  final String contentText;
+  final void Function() onYesPressed;
+  final void Function() onNoPressed;
+
+  AppYesNoDialog({
+    Key key,
+    @required this.titleText,
+    @required this.contentText,
+    @required this.onYesPressed,
+    @required this.onNoPressed,
+  }) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return AlertDialog(
+      title: Text(titleText),
+      content: Text(contentText),
+      actions: <Widget>[
+        FlatButton(
+          child: Text("Yes"),
+          onPressed: onYesPressed,
+        ),
+        FlatButton(
+          child: Text("No"),
+          onPressed: onNoPressed,
+        )
+      ],
+    );
+  }
+}