New Feature: wysiwyg design time editing - add and remove spacer widgets

[Steve-Mcl]

closes #1479

Description

New feature - ability to add and remove widgets in the dashboard at edit time.

Refactors a lot of the non-store stuff into a new store named wysiwyg - this is primarily to take advantage of actions and preparation for #1481

This is an extension of (and thus) merges into #1468

Demo

Related Issue(s)

#1479

Checklist

• I have read the contribution guidelines
• Suitable unit/system level tests have been added and they pass
• Documentation has been updated
  • Upgrade instructions
  • Configuration details
  • Concepts
• Changes flowforge.yml?
  • Issue/PR raised on FlowFuse/helm to update ConfigMap Template
  • Issue/PR raised on FlowFuse/CloudProject to update values for Staging/Production

Labels

• Includes a DB migration? -> add the area:migration label

[NZHYDROGEN]

There is an issue with the layout editor in 1.21.0, its just loading a blank page

[NZHYDROGEN]

There is an issue with the layout editor in 1.21.0, its just loading a blank page

when using console it is showing this error: Failed to load module script: Expected a JavaScript module script but the server responded with a MIME type of "text/html". Strict MIME type checking is enforced for module scripts per HTML spec.

[joepavitt]

@NZHYDROGEN do you have anything different about your Node-RED setup? Proxy? How is it hosted?

[colinl]

@NZHYDROGEN what browser and version are you using? Can you try a different browser?
Try restarting node-red and clear the browser cache (via the browser menus not hot key).