Port to .NET 5 about gorgon

[Tape-Worm]

As of right now the following assemblies have been converted:

• Core
• FileSystem
  • File System Plugins
• Input
  • Input Plugins
• Graphics Imaging
• All examples related to the above assemblies

This was quite easy to do, and required very few code changes.

[Tape-Worm]

Waiting on Krypton to be converted fully for .NET Core 3.1. Once this is done we can move forward.

[Tape-Worm]

For the next minor version update, all projects in Gorgon have been converted to the new simplified project format in preparation for moving to .NET 5 (or maybe 6 if they can't get their Winforms designer together.. so buggy).

Along with updating targets to .NET 5, the code will be updated to utilize C# 8/9 features such as records.

However, until the .NET forms designer is actually useful (currently Krypton has a ton of trouble with it), work will have to pause.

[Tape-Worm]

A workaround that allows the forms to be edited using the old .NET framework IDE seems to be working. The .NET 5 upgrade is underway...