feat(editor): Add initial code for NodeView and Canvas rewrite (no-changelog)

[alexgrozav]

Summary

This PR contains the initial code for the NodeView and Canvas rewrite. We're going through a big migration to VueFlow which should take our editor experience to the next level.

• To enable, add the features.NodeViewV2 key with a true value to localStorage
• To try it out, navigate to /workflow-v2/:id for any workflow
• Adds NodeView.v2.vue containing basic covered functionality
• Adds new Canvas.vue component and sub-components for nodes, edges, handles, buttons

Current supported features:

• Rendering Nodes and Connections
• Adding nodes
• Moving nodes
• Connecting nodes
• Saving the workflow

We're merging this to facilitate n8n team contributions and progressive reviewing of the added code.

Related tickets and issues

https://linear.app/n8n/project/nodeview-v2-58fb8eb1701b/issues

Review / Merge checklist

• [x] PR title and summary are descriptive. Remember, the title automatically goes into the changelog. Use (no-changelog) otherwise. (conventions)
• [x] Docs updated or follow-up ticket created.
• [x] Tests included.

  A bug is not considered fixed, unless a test is added to prevent it from happening again. A feature is not complete without tests.