fix: Pin cpu platform

[Dorus]

fixes #299

This sets our builds to the specific platform the dlls we ship.

We could support more platforms, but that would require us to include different dlls. This pr focus just on removing the warning about the architecture missmatch (any cpu) and the dlls we use.

[shpaass]

As none of us are proficient in the sln files, it would be very informative if you explained every change that was done to the files. Essentially, it is the equivalent of me asking "what does it do?" and "why do we need this change?" to every change in the diff.

[Dorus]

1. csproj changes: These just tell the project is compatible with this platform option.
2. .sln changes: This tells visual studio and/or msbuild (the underlying runner of dotnet build/publish) what platforms we support. In our case we support Debug and Release as solution configuration and x64 and ARM64 as platform. There is a bit of aliassing here telling the tools what solution configuration matches with what csproj configuration. All of this is set up with the Configuration Manger in visual studio
   
   You could in theory use different platforms and different set of projects to build for each config, but i've just set it to build everything under the same selected platform.
3. build.sh changes: This tells dotnet to pass paramters to msbuild with the -p flag. The Plaform flag tells msbuild what platform to pick from, since we now want to make sure OSX is build on the correct platform, and not Any CPU that I've removed.

And to why we removed Any CPU: Obvious to get rid of the warning. But more precise, we import DLLs that are only comnpatible with specific platforms, by setting the platform on the project build, we make dotnet check for this platform requirement at startup rather than crash when it tries to load an incompatible dll. Note this wont actually change what's build otherwise, the resulting dotnet code is still platform independent.

[shpaass]

Thank you for the explanation! I guess that the next step of the review would be to figure out why the CI check fails and what we need to do about it.

[Dorus]

By the look, the CI test run the wrong platform. Let me see if i can update the CI commands.

[Dorus]

Yay, that took a few more tries than i would like to admit. First needed to find the right file, then the right command. Anyway i think i got it since the CI check is now green. I've rebased and squashed all changes into one commit.

[shpaass]

I might be wrong, but the criterion of #299 being fixed is that when you run dotnet format, there's no line Warnings were encountered [...].

This line is still present with the current PR.

[Dorus]

This should fix the

There was a mismatch between the processor architecture of the project being built

error. It was present for me when i started working on this, and gone after these changes. However right now i do not get that error anymore at all, both on master or my branch. I'm also not getting any other errors from dotnet format, both locally and from the git hub build.

[shpaass]

That's curious because I still get this error on your branch.