C# module bindings for Procedures

[rekhoff]

Description of Changes

Implements the C# module bindings for Procedures (#3510)

API and ABI breaking changes

None

Expected complexity level and risk

2

Testing

• Locally tested against existing C# Procedures regression test client (minus the Transaction and HTTP portions, as those are not in this change).

[JasonAtClockwork]

Reviewed the code and ran the regression tests with no troubles; all looks good to me. The only question I have is if we should be adding checks to Codegen.Tests/fixtures/diag/Lib.cs and Codegen.Tests/fixtures/server/Lib.cs? Or maybe add that once all the pieces are in?

One test that would be good is a procedure that returns a non-SpacetimeDB.Type. This should fail due to the ReturnType.BSATNName but would be good to track that.

[JasonAtClockwork]

Ahh just realized the client-side tests are not there for regression, I've added one locally just to make sure procedures are calling but you'll want to mirror what the /regression-test/procedure-client - once the TX pieces are in place we can probably delete that entire runner too.

[rekhoff]

This are some great ideas for additional tests. I was intending on getting add a more robust set of tests once the other pieces are in place, and migrate the procedure-client into the existing client regression test. I'll add the test suggestions to the list to implement as part of the other procedure pieces implementations.