Perform partial trimming in client releases

[alexrp]

c9afc56 removed trimming from the build system. While full trimming is impractical for us, we could explore partial trimming. I think we only do reflection on our own assemblies, so there should be no issue with trimming any third-party assemblies that declare themselves trimmable.

Right now, a client release archive with maximum compression is around 171 MB, which seems rather excessive.

Depends on:

• Reimplement packet serialization with source generators #108

[alexrp]

A few things:

• Anything the bridge module needs from the BCL has to be preserved with a descriptor file.
• We invoke Unsafe.As<T>(object) through reflection in a few places. This method needs to be preserved with a descriptor file.
• Our reflection usage needs to be audited and warnings suppressed where we only reflect on our own code.
• Our use of the Avalonia.ReactiveUI package seems to cause quite a lot of warnings. We might be able to do without it.

[alexrp]

We'll try to switch to the MVVM Toolkit to make this happen.

https://learn.microsoft.com/en-us/dotnet/communitytoolkit/mvvm

[alexrp]

bc0b499