[Feature]: Fleet in-place update

[jvstme]

Problem

Updating any fleet properties requires stopping all runs that are using the fleet and recreating it, including recreating the underlying VMs in cloud fleets.

Solution

Support in-place update for all properties that could be updated without recreating the fleet.

Note that some properties could be updated without stopping or starting any instances (blocks, placement for SSH fleets, etc), while other properties may require some instances to be started or stopped (nodes, resources, etc).

In-place update for different properties can be implemented in different sub-issues.

Workaround

No response

Would you like to help us implement this feature by sending a PR?

Yes