Improve debugging

[elringus]

Currently, even in debug builds, when an exception occurs in the managed C# code, the error information is very limited:

marshal-to-js.ts:420 Uncaught ManagedError: How low hello!
an @ marshal-to-js.ts:420
gn @ managed-exports.ts:316
(anonymous) @ invoke-cs.ts:148
setSkipMode @ index.mjs:358
(anonymous) @ playback.tsx:29
(anonymous) @ playback.tsx:104
(anonymous) @ button.tsx:41

We are copying the debug artifacts to the output directory:

bootsharp/src/cs/Bootsharp/Build/Bootsharp.targets

Lines 168 to 179 in 79c6780

	<!-- Publish debug symbols and maps when aggressive trimming is disabled. -->
	<ItemGroup>
	<BootsharpMaps Include="$(BootsharpBuildDirectory)/*.map"/>
	<BootsharpSymbols Include="$(BootsharpBuildDirectory)/*.symbols"/>
	<BootsharpPdbs Include="$(BootsharpBuildDirectory)/*.pdb"/>
	</ItemGroup>
	<Copy Condition="'$(BootsharpAggressiveTrimming)' != 'true' And '$(BootsharpEmbedBinaries)' != 'true'"
	SourceFiles="@(BootsharpMaps)" DestinationFolder="$(BootsharpBinariesDirectory)"/>
	<Copy Condition="'$(BootsharpAggressiveTrimming)' != 'true' And '$(BootsharpEmbedBinaries)' != 'true'"
	SourceFiles="@(BootsharpSymbols)" DestinationFolder="$(BootsharpBinariesDirectory)"/>
	<Copy Condition="'$(BootsharpAggressiveTrimming)' != 'true' And '$(BootsharpEmbedBinaries)' != 'true'"
	SourceFiles="@(BootsharpPdbs)" DestinationFolder="$(BootsharpBinariesDirectory)"/>

— but it looks like they are not being used, even when explicitly setting <DebugType>full</DebugType>.

Ideally, we'd like to make the JS debugger work with Bootsharp, but at the very least, we need to find a way to make the errors contain legible stack traces.

If anyone is interested in working on this or has ideas on how to tackle the issue — please share them here.