Extism .NET PDK Beta

[mhmd-azeez]

• Implement all of the PDK functions
• Allow users to import functions: We are now using DllImport instead of [MethodImpl(MethodImplOptions.InternalCall)] and we are also targeting .NET 8 now.
• Make sure Mono.Cecil is not copied to plugin output dir
• For some reason, the Rust runtime can't run .NET plugins after v0.1. I am not sure what has changed between 0.1 and 0.2. I am using the Go SDK to run the samples. This was because Mono expects at least one command line argument. I have wrapped mono_runtime_run_main to ensure that we pass at least one argument
• Write some instructions in the README
• Link to discord in the README
• Create CI action
• Test the nuget package locally
• Create release action

[zshipko]

I'm curious what the error from the Rust runtime is?

I will try to get an environment to run this setup on my machine!

[mhmd-azeez]

@zshipko

I'm curious what the error from the Rust runtime is?

as we discussed before, the issue was this: https://github.com/dotnet/runtime/blob/4101144c8dde177addfb93ac46425fd1a8604f7a/src/mono/mono/metadata/object.c#L4175

This is now fixed in: 804c738

Side note: it seems like wasmtime passes its own command line args along to the module. e.g: wasmtime run plugin.wasm.

[mhmd-azeez]

@zshipko @bhelx
Alright, I think this PR is ready for your review folks! It has taken shape pretty nicely :)