Fixed MacOS build plus some random bug fixes

[basdp]

I have fixed the AOT build for MacOS (especially for Apple Silicon/ARM64).

• A VST3 bundle should emit a bundleEntry and bundleExit symbol, like it's done in the VST3SDK:
  https://github.com/steinbergmedia/vst3_public_sdk/blob/3f20bcbf36283b1e5c450e088571be6226cd4e64/source/main/macmain.cpp#L71
• Changed target framework for NPlug.Proxy to net8.0, as MacOS AOT builds will fail otherwise (error message about Native AOT not available on this platform with net7.0`).
• Fixes some minor warnings.
• This also fixes Controller exposes itself as additional effect to the host #5, duplicate entry in DAW, where the controller wrongly exposes itself as an audio effect.

[xoofx]

Thanks!