The coordinator now sends an immediate `DataflowStartTriggered` reply when receiving a `DataflowStart` command. This enables the CLI to directly attach to the dataflow and observe the build output.

To wait until the build/spawning is done, this commit introduces a new `WaitForSpawn` command, to which the coordinator replies with a `DataflowSpawned` message once the node has been started. We use this command for the `dora build` command.

Instead of running all the build commands directly, run them on their intended target machines through the coordinator.

This commit is a breaking change because a coordinator connection is now required for `dora build`.

but keep zenoh log level at WARN level

The previous machine ID is still used, but optional. Users don't need to ensure that the chosen machine IDs are unique anymore because they are augmented with a UUID.

Runs a dataflow locally, without requiring any any daemon or coordinator
processes. Multi-machine dataflows are not supported. The default log
level is set to `INFO`, overwriting it is possible by setting the
`RUST_LOG` environment variable.

This exposes the internal `dora daemon --run-dataflow` command that we
use for testing.

This addition was proposed in
https://github.com/orgs/dora-rs/discussions/698#discussioncomment-11125465
.

The second commit adds a ctrl-c handler. On first ctrl-c, we send a stop
command to all nodes. On second ctrl-c, we exit immediately and kill all
spawned nodes. On third ctrl-c, we abort the process directly without
waiting (child processes keep running).

Make `dora-message` a dependency of `dora-core`, instead of the other way around. This way, we can continue to freely bump the version of `dora-core` with the other workspace crates, without introducing errors such as #708.

Runs a dataflow locally, without requiring any any daemon or coordinator processes.

This exposes the internal `dora daemon --run-dataflow` command that we use for testing.

This addition was proposed in https://github.com/orgs/dora-rs/discussions/698#discussioncomment-11125465 .