Migrate C# ModuleDef to V9

[RReverser]

Description of Changes

This migrates module definition to V9 for C# modules.

Note that it's based off #1573 which is why the target branch is currently not master. It will be changed and the Git history will be cleaned up when the base PR is merged.

For now the C# modules compile with new codegen & definitions, but I have no way to test it until we migrate spacetime generate to V9 so that we could run SDK tests against it. That's why I'm marking this PR as draft until that's resolved.

API and ABI breaking changes

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Expected complexity level and risk

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Testing

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[RReverser]

Updated this PR to latest definitions. Thanks to #1661 + @coolreader18's #1675, I can verify that I'm now producing correct ModuleDef as it can generate Rust sources from a C# module. Further testing is still blocked by lack of V9 support in the actual runtime - I'm hitting

SpacetimeDB/crates/core/src/host/wasm_common/module_host_actor.rs

Lines 159 to 163 in 71c7722

	_ => {
	return Err(InitializationError::Describe(
	DescribeError::UnimplementedRawModuleDefVersion,
	))
	}

so leaving this PR as a draft.