Virtual DOM implementation

[jedimahdi]

There are multiple reasons which makes snabbdom unsuitable for the Monarch.

• It doesn't separate diffing and patching processes. So we cannot schedule these two different kind of tasks.
• The diffing process is recursive which at least comes with two drawbacks.
  • It blocks the main thread of JavaScript. So UI become unresponsive during the diff.
  • The process can't interrupt at some point.
• The virtual DOM tree is not extensible. So we cannot have custom nodes (e.g. thunk, async, suspense, etc...) easily.

BTW here we are with a new capable virtual DOM implementation which is highly inspired by the elm/virtual-dom.

Essential features:

• The diffing and patching processes are completely separate. So can become scheduled differently.
• The diffing process is not recursive so it doesn't block the main thread and also it can interrupt if a new VirtualDomTree has been created.

[the-dr-lazy]

This PR is pending for #6

[the-dr-lazy]

This PR closes #5.