Proposed strategy to support WASM in D

[AnimusPEXUS]

also I've collected some useful links for various WASM and JS 
resources related to WASM<>JS integration for ppl less to Google. 
here

* 
https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions
* 
https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API
* 
https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Browser_support_for_JavaScript_APIs
* https://developer.mozilla.org/en-US/docs/Web
* https://developer.mozilla.org/en-US/docs/Web/API
* https://developer.mozilla.org/en-US/docs/WebAssembly
* 
https://developer.mozilla.org/en-US/docs/WebAssembly/JavaScript_interface
* 
https://developer.mozilla.org/en-US/docs/WebAssembly/JavaScript_interface/Memory/grow
* 
https://developer.mozilla.org/en-US/docs/WebAssembly/Using_the_JavaScript_API
* https://developer.mozilla.org/en-US/docs/Web/JavaScript
* 
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference
* https://github.com/adamdruppe/webassembly
* 
https://github.com/bytecodealliance/wasmtime/blob/main/docs/WASI-documents.md
* 
https://github.com/bytecodealliance/wasmtime/blob/main/docs/WASI-intro.md
* https://github.com/ldc-developers/ldc
* https://github.com/WebAssembly/proposals
* 
https://github.com/WebAssembly/tool-conventions/blob/main/BasicCABI.md
* 
https://github.com/WebAssembly/tool-conventions/blob/main/Linking.md
* 
https://github.com/WebAssembly/WASI/blob/main/phases/snapshot/docs.md
* https://lld.llvm.org/WebAssembly.html
* https://llvm.org/doxygen/namespacellvm_1_1wasm.html
* https://llvm.org/doxygen/namespaces.html
* 
https://rob-blackbourn.github.io/blog/webassembly/wasm/strings/javascript/c/libc/wasm-libc/clang/2020/06/20/wasm-string-passing.html
* 
https://stackoverflow.com/questions/41353389/how-can-i-return-a-javascript-string-from-a-webassembly-function
* https://wasi.dev/
* https://webassembly.github.io/spec/core/
* https://webassembly.github.io/spec/core/exec/index.html
* 
https://webassembly.github.io/spec/core/exec/instructions.html#memory-instructions
* https://webassembly.github.io/spec/js-api/index.html
* https://webassembly.github.io/spec/js-api/#memories
* https://webassembly.github.io/spec/web-api/index.html
* https://webassembly.org/specs/
* 
https://wiki.dlang.org/Generating_WebAssembly_with_LDC#Calling_external_functions
* https://wiki.dlang.org/LDC-specific_language_changes
* https://wiki.dlang.org/Runtime_internals
* https://wiki.dlang.org/Using_LDC
* https://www.llvm.org/docs/ExtendingLLVM.html
* https://www.w3.org/TR/wasm-core/