Description

This pull request converts the Talk screen to NUI. It should functionally identically to before, although there may be some minor visual differences.

Testing

Start a new game (or continue an existing one)
Fly towards the starting station until the Talk button is enabled
Verify that the talk screen opens when you click on the Talk button
Verify that each of the buttons on the talk screen behaves as before e.g.
- Verify that the buy screen opens when you click on the Buy button (or press the B key)
- Verify that the sell screen opens when you click on the Sell button (or press the S key)
- Verify that the Change Ship screen opens when you click on the Change Ship button (or press the C key)
- Verify that the Hire Ship screen opens when you click on the Hire button (or press the H key)
- Verify that the talk screen closes when you click on its Close button (or press the Escape key)
Test that this works for both the starting station and the stations found on planets

This supersedes #639.
This depends on #664 and #665.
Until #664 and #665 are merged, it might be easier to view the changes made in this pull request by viewing the diff between this and #665 at https://github.com/BenjaminAmos/DestinationSol/compare/nui-screen-conversion/main-game-screen...nui-screen-conversion/talk-screen.