[shell]: Add thread control features through shell

This commit extends the shell command functionality by
adding three new operations for thread management.
kernel thread suspend <thread_id>:
Suspends any thread based on its identifier.
kernel thread resume <thread_id>:
Resumes the thread that was previously suspended.
kernel thread kill <thread_id>:
Terminates any thread based on its identifier
These extended commands are useful for controlling
any threads through Zephyr Shell.

Signed-off-by: S Swetha <s.swetha@intel.com>