Handle "Waiting for user session" Dev Box config status; Fix slow loading

[huzaifa-d]

Detailed description of the pull request

1. Currently when applying a config to a Dev Box, if the user isn't signed in, Dev Box REST APIs return a "Waiting for user" status. This is shown in the UI as an Adaptive Card. But Dev Box also needs a little over a couple of minutes to make sure all required services are running once a user does login. This PR adds logic to handle the status better including situations where the user might log off again. And adds more wait.
2. This PR also fixes the slower loading of the compute systems. This is done by parallelizing the query and moving pool mapping code to a background thread.
3. Adds some failure handling for configs. This will be done in more detail in a future PR.

Validation steps performed

Checked

PR checklist

• [x] Closes #https://github.com/microsoft/devhome/issues/2774
• [x] Closes #https://github.com/microsoft/devhome/issues/2736
• [ ] Tests added/passed
• [ ] Documentation updated