[Enhancement] Create SplitView Region App

[DamianSuess]

Description

As a user, I want to simplify the full-app with a basic SplitView app. Keep boiler-plate code to the bare-minimum with regions.

Proposed Project Templates

1. Basic Empty App
2. Regions with SplitView App
   • MainWindow using SplitView
   • Regions: SideBarRegion & ContentRegion
   • Views: HomeView, SideBarView
3. Module App
   • Multi-project with modules
   • Event Aggregator example
4. Prism.Avalonia - Event Project - project sample using Events
5. Prism.Avalonia - Full Project
   • With SplitView Project
   • Navigation example
   • Region example
   • MessageBox Dialog example
   • Notifications example

Might not need #4 as it is overkill