Render disabled tabs correctly

[Steve-Mcl]

closes #5

Description

Respect the disabled property of a tab and disable nodes accordingly. also, tab label will be shown with dotted outline, italic text and a prepended fa-ban icon

Before & after

Related Issue(s)

5

Checklist

• [x] 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

• [ ] Backport needed? -> add the backport label
• [ ] Includes a DB migration? -> add the area:migration label