NodeEditor: Update Flow.js lib and added TreeView to create Node

[sunag]

Description

TreeView

This PR is in line with others that I am finalizing. ContextMenu is not a very appropriate Menu for large content options, in that sense I created a TreeView where we could also search for Nodes by a filter field.

Live:
https://raw.githack.com/mrdoob/three.js/dev/examples/webgl_nodes_playground.html

[LeviPesin]

Something strange is going on with the checks on this PR... They are running for about 4 hours, still did not finished, and this doesn't allow to run queued CI checks on other PRs and they stale.

[Mugen87]

Nit: There are two places were superfluous arguments are passed to a super() call:

three.js/playground/libs/flow.module.js

Lines 3073 to 3077 in 4e361e9

	class ContextMenu extends Menu {
	constructor( target = null ) {
	super( 'context', target );

and

three.js/playground/libs/flow.module.js

Lines 3265 to 3269 in 4e361e9

	class CircleMenu extends Menu {
	constructor( target = null ) {
	super( 'circle', target );

Probably best to fix this in the main repository.