Improved PID documentation #1828

Job	Run time
read_targets_from_file / read_targets_from_file	4s
basic_build (cf2)	3m 33s
basic_build (bolt)	3m 30s
basic_build (tag)	3m 20s
basic_build (flapper)	3m 31s
features (bosch.conf)	3m 22s
features (loco_tdma.conf)	3m 23s
features (loco_tdoa2.conf)	3m 28s
features (loco_tdoa3.conf)	3m 30s
kbuild-targets (allyesconfig)	3m 25s
features (loco_tdoa3_all.conf)	3m 24s
kbuild-targets (allnoconfig)	3m 15s
apps (examples/app_hello_world)	2m 29s
features (bigquad.conf)	3m 21s
apps (examples/app_hello_world-cpp)	2m 19s
kbuild-targets (randconfig)	3m 19s
features (app_api.conf)	3m 29s
apps (examples/app_hello_file_tree)	2m 23s
apps (examples/app_peer_to_peer)	2m 20s
apps (examples/app_p2p_DTR)	2m 20s
apps (examples/app_stm_gap8_cpx)	2m 23s
apps (examples/demos/app_push_demo)	2m 29s
apps (examples/demos/swarm_demo)	2m 20s
apps (examples/demos/app_wall_following_demo)	2m 18s
	1h 9m 15s

Provide feedback