fix: execute the Arduino CLI without a shell

[kittaakos]

Motivation

Execute the Arduino CLI process without a shell.

• security reasons,
• some users might not have the %ComSpec% set on Windows, and CMD.exe is not on the $PATH

Remove the obsolete CLI daemon watcher process. Before arduino/arduino-cli#488, IDE2 required a way to stop the daemon process if the parent (backend) process crashed. However, this mechanism
is no longer necessary, as the CLI daemon process is not actually a true daemon process.

Change description

Other information

To verify:

• Arduino IDE starts, and the CLI is fully functional when there is a whitespace in the path to your IDE2 installation.
• Start IDE2. Open the task manager/activity monitor on your system. See that arduino-cli process is running. Kill the IDE2 process. See that the arduino-cli process is not running.

Closes #2112
Ref: #2067

Reviewer checklist

• PR addresses a single concern.
• The PR has no duplicates (please search among the Pull Requests before creating one)
• PR title and description are properly filled.
• Docs have been added / updated (for bug fixes / features)

[per1234]

I verified this fixes the problem with Arduino failing to start up with errors like:

daemon ERROR Error: spawn C:\WINDOWS\system32\cmd.exe ENOENT
    at Process.ChildProcess._handle.onexit (node:internal/child_process:282:19)
    at onErrorNT (node:internal/child_process:480:16)
    at processTicksAndRejections (node:internal/process/task_queues:83:21)

in cases where there is a problem with the user's ComSpec environment variable:

• Variable is not defined (example)
• Variable is set to an incorrect path (example)
• cmd.exe has been removed (example)
• Variable has been set to the path of an incompatible shell (example)

Thanks Akos!