ntp: T4909: Rewrite NTP op mode in new format

ntp: T4909: Rewrite NTP op mode in new format

Adapts ntp.xml.in to reference new ntp.py file
Add ntp.py
Adds a check to ntp.py to verify if the ntp service is configured
Adds raw mode to ntp.py
For raw output, replaces the original method of parsing the command line output FROM re.split+regex TO csv.reader.
Separates chrony commands into equivalent functions show_tracking, show_sources, source_sourcestats and show_activity
Revises the names of raw dictionary keys variables to be lowercase
Corrects a comment typo and renames function name used for raw mode

(cherry picked from commit d2a82c30695c2f4265dc5ca2165d27d5aa3e2cef)