Playnite 9 support

[darklinkpower]

Changes:

• Updated to support Playnite SDK 6.1.0
• Added installer manifest to add to Playnite addons database. This is a placeholder and should be modified when doing the release.
• Use new Playnite settings model introduced in Playnite 9
• Formatting fixes:
  1. Use curly braces to encapsulate bodies
  2. Use camelCase for private properties for consistency
  3. Other minor fixes

I also did a little rework since I found some things that could be improved in the project:

1. The project was outputting a lot of libraries during build, and most were unused

Before

After

• The project didn't have the extension.yaml manifest so I added it
• The icon and extension were not outputting to the build output directory

2. Use Models directory and namespace for models to improve the project structure

[darklinkpower]

It's tested but here is a build in case you want to check the changes VNDBMetadata_1_2.zip

Regarding the version of the extension, maybe it would be worth jumping to 2.0, considering it's a SDK breaking change.

[davidmwest]

Looks great to me.

[davidmwest]

I've been using this version of the plugin with the latest version of Playnite for a week now. I haven't seen any regressions. If anything, the plugin seems improved, although that might just be my increased literacy with VNDB.