Refactored UI code and DISASM view massive bug fixed

[maximilien-noal]

Description of Changes

• fix: disasm view showed the wrong code, unless the window was closed and reopened
• feature: the disasm view now has the start address and number of instructions shown configurable
• refactor: the DebugViewModel and MainWindowViewModel are more SOLID
• refactor: the relationship between ViewModels are simpler
• refactor: and more UI code deleted / simplified
• split up and simplified xaml code
• Use of DataTemplates to enable lazy loading, so the Debug window loads faster (hopefully)
• Those DataTemplates will enable future features, such as multiple Memory and Disasm views opened at the same time

Rationale behind Changes

Enable more contributions to the UI. Makes the UI code easier to maintain. Makes the implementation of future debug features easier.

Suggested Testing Steps

Already tested, and I can't wait for people to test this. :)

[maximilien-noal]

I fixed the last commit. :)

Thank you for your review!