2. Add HotReload to Just Clusters

[rasswanth-s]

Description

The PR adds hot reload mode to just clusters.

Depends on PR: #9307

Affected Dependencies

List any dependencies that are required for this change.

How has this been tested?

• Describe the tests that you ran to verify your changes.
• Provide instructions so we can reproduce.
• List any relevant details for your test configuration.

Checklist

• I have followed the Contribution Guidelines and Code of Conduct
• I have commented my code following the OpenMined Styleguide
• I have labeled this PR with the relevant Type labels
• My changes are covered by tests

[yashgorana]

let's not split the justfile at this moment. we'll evaluate it later. also since the command is devspace dev can you replace it with dev-high dev-low and so on?

[yashgorana]

also #9305 changes the variable names

[rasswanth-s]

Superseded by #9309