Add ability to run a cloud test

[Llandy3d]

We should add the ability to run a cloud test from inside the application.

This requires that the user is able to login to his grafana's account and select a stack where the test run should run. If multiple stacks are present we should decide if we pick one by default or let the user select one.

This requires

• UX to be designed
• Ability to login via grafana account
• Ability to swap the selected stack
• Ability to start a cloud run and view it in grafana

blocked by

• https://github.com/grafana/k6-cloud/issues/3235