CI: Customise pre-staging environment

[ppawlowski]

Description

This PR extends the "deploy from branch" pipeline by adding extended initialisation setup script. In result, each pre-staging environment created for particular PR will be configured with the set of users, teams, instances and devices specified in the related issue.

Related Issue(s)

#3668

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

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

[ppawlowski]

@hardillb Please review from the technical perspective.
@Steve-Mcl please review if the pre-staging environment related to this PR meets the requirements in terms of configuration.

[Steve-Mcl]

From a user test POV, this PR makes our lives so much better - really good stuff.

As mentioned in slack, I believe we need more stacks - I will raise follow up issue

Good to merge once tests pass.