Add support for chrony

It might be interesting to support reporting stats from chrony, to see how they change over time.

Sample Output

Example output from chronyc tracking.

Stratum 1

Reference ID    : 50505300 (PPS)
Stratum         : 1
Ref time (UTC)  : Fri Jun 23 13:16:42 2023
System time     : 0.000000243 seconds slow of NTP time
Last offset     : -0.000000209 seconds
RMS offset      : 0.000000543 seconds
Frequency       : 5.215 ppm fast
Residual freq   : -0.003 ppm
Skew            : 0.098 ppm
Root delay      : 0.000000001 seconds
Root dispersion : 0.000002052 seconds
Update interval : 1.0 seconds
Leap status     : Normal

Stratum 2

Reference ID    : 0A000111 (Stratum1.ReaperLegion.net)
Stratum         : 2
Ref time (UTC)  : Fri Jun 23 04:51:44 2023
System time     : 0.000034337 seconds fast of NTP time
Last offset     : +0.000052885 seconds
RMS offset      : 0.000019577 seconds
Frequency       : 1.549 ppm slow
Residual freq   : +0.094 ppm
Skew            : 0.069 ppm
Root delay      : 0.000492951 seconds
Root dispersion : 0.000039761 seconds
Update interval : 128.7 seconds
Leap status     : Normal

Stratum 4

Reference ID    : A83DD74A (168.61.215.74)
Stratum         : 4
Ref time (UTC)  : Tue Aug 01 01:44:41 2023
System time     : 0.001303686 seconds slow of NTP time
Last offset     : -0.000234149 seconds
RMS offset      : 0.001895696 seconds
Frequency       : 4.772 ppm slow
Residual freq   : -0.311 ppm
Skew            : 17.235 ppm
Root delay      : 0.076234169 seconds
Root dispersion : 0.031941257 seconds
Update interval : 64.4 seconds
Leap status     : Normal

And in CSV mode (-c):

A83DD74A,168.61.215.74,4,1690854281.436998265,0.001293664,-0.000234149,0.001895696,-4.772,-0.311,17.235,0.076234169,0.031962913,64.4,Normal