rpc_wrappers: thread_stats: added

[JordanYates]

Add a wrapper for the thread_stats RPC, displaying stack usage. example output:

Thread                  Stack Used    Stack Size    Stack %    CPU %
--------------------  ------------  ------------  ---------  -------
hostap_handler                5204          5800         89        0
main                          1788          2048         87        0
ep_proc                       1708          2048         83        0
logging                        608           768         79        0
net_mgmt                      3588          4600         78        0
nrf70_intr_wq                  772          1024         75        0
epacket_udp_thread            1484          2048         72        0