Changes for Jellyfin 10.9

[harshithmohan]

• Now uses dotnet 8.0, same as Jellyfin 10.9
• Changed IServerEntryPoint into IHostedService
  • RunAsync changed to StartAsync
  • Dispose changed to StopAsync
  • GC.SuppressFinalize(this); is not needed anymore
  • Added new class PluginServiceRegistrator to register UserDataServerEntry and SessionServerEntry , required for IHostedService to work. It doesn't work automatically like IServerEntryPoint had.
• MediaTypes now uses MediaType enum instead of string
• Tested on 10.9.1
• Fixes Jellyfin 10.9 released #124
• Not sure if build.yaml is being used but changed it anyway

[harshithmohan]

I forgot to update the Dockerfile. My bad 🤦

[vosmiic]

I forgot to update the Dockerfile. My bad 🤦

No worries, looks like the docker build command was failing too because --output is no longer supported.
There still seems to be an issue with the nuget signatures but I might merge it anyway and fix it at some point over the next few days as this is preventing users from using the plugin if they have updated Jellyfin.

Thank you for creating this PR and getting the plugin up to date for the new Jellyfin version!