Pipeline: Restructure Pipeline Pages

[Pezmc]

Description

Restructures the pipeline and pipeline stage pages in the front end to fall under applications and pipelines routes.

i.e.

Application > Create Pipeline
Application > Pipeline > Create Stage

Previously all page routes were sat at the team level, which meant the application and pipelines had to be reloaded for each page. This way, the application can be passed down into the pipeline, which then passes the pipeline down into the create stage form.

As part of this:

• No longer shows instances already in use in the pipeline in the dropdown
• Disables the form if no instance is selected

Related Issue(s)

Part of #2124

Checklist

• I have read the contribution guidelines
• [-] Suitable unit/system level tests have been added and they pass - Happening in Application > Pipelines #2075
• Documentation has been updated
  • Upgrade instructions
  • Configuration details
  • Concepts
• Changes flowforge.yml?
  • Issue/PR raised on flowforge/helm to update ConfigMap Template
  • Issue/PR raised on flowforge/CloudProject to update values for Staging/Production

Labels

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