testing: update testing scripts

The following scripts were removed:
ChToFreq.sh
FreqToCh.sh
HOW TO USE SCRIPTS.txt
Load Convert Scripts.ttl
Load MR Scripts.ttl
how to load ap multirole.txt
how to load sta multirole.txt
sta_add.sh
sta_remove.sh

Signed-off-by: Igal Chernobelsky <igalc@ti.com>