[WASM] Node Support

[Daniel-Genkin]

WORK IN PROGRESS

This PR adds the missing pieces for NodeJS support to MONO WASM!

How does it work

The main differences between this and running the console sample regularly for v8 is that dotnet.js is modularized so we use require to load it. We now also have a package.json and package-lock.json files as well as the node_modules folder. Besides that, most changes to the code were related to various NodeJS related nuances such as the scoping of this but are ignored by the browser.

How to run locally

1. Build the artifacts folder to use the Node -os flag (ex: ./build.cmd mono -os Node -c Debug) (make sure to have libs already built as browser. For some reason it fails when building libs for node but I am working on it). Note however that although this will build, since the libs are built for another target, they won't be reachable while running. However, builds will still succeed so generated code inspection is possible.
2. publish the console sample with /p:TargetOS=Node (ex: ./dotnet.cmd publish /p:TargetArchitecture=wasm /p:TargetOS=Node Wasm.Console.Sample.csproj -c Debug).
3. Cd into the \src\mono\sample\wasm\console\bin\{CONFIGURATION}\AppBundle folder and run ./run-node.cmd or run-node.sh depending on your OS. You should see the regular console sample output. Note that you can also use the NPM test task to achieve the same result (i.e. npm test).

See the open question sections for a link to branch that successfully builds and runs in node.

TODO LIST

• Get it to run manually by building and publishing the console sample app for the browser build target and then manually executing the output via node --trace-warnings runtime.js --run Wasm.Console.Sample.dll
• Add a new Build target to automatically copy over the package.json file and run npm install on it
• Make MSBuild automatically change the emcc Modularize flag based on build target
• Add a new MSBuild TargetOS for NodeJS
• Fix the new Node Build target in MSBuild so that it builds libs properly
• Merge previous PRs ([WASM] Converted mono-config.js to mono-config.json #53606, [WASM] Enabled strict mode on all JS files #54011, [WASM] Normalize runtime-test.js #54281) to cleanup the code
• Other miscellaneous clean up work
• Double check with someone more experienced with MSBuild if there is a better way to add the Node target. It behaves the same as Browser with the only exception being modularizing the emcc output.
• Add a CI build for Node (Should this be a separate PR?)

Open Questions

• Should this be a new TargetOS (specified by -os Node) or should it be an additional flag/parameter that is passed while building for Browser (i.e. /p:ForNode=True)? To see a working copy of the flag option see my other branch wasm-node-via-extra-flag

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this PR. If you have write-permissions please help me learn by adding exactly one area label.

[Daniel-Genkin]

Closing PR as we decided to use the flag instead of $(TargetOS).
See that PR here: #54640