TS-4380: Initial traffic_ctl support for server start/stop.
TS-4380: Initial traffic_ctl support for server start/stop.

Implement a basic version of the "server start" and "server stop"
subcommands for traffic_ctl. This brings feature parity with
traffic_line.

taoyunxing/trafficserver,dyrock/trafficserver,persiaAziz/trafficserver,clearswift/trafficserver,rahmalik/trafficserver,davidbz/trafficserver,rpufky/trafficserver,rpufky/trafficserver,dyrock/trafficserver,reveller/trafficserver,chitianhao/trafficserver,taoyunxing/trafficserver,taoyunxing/trafficserver,PSUdaemon/trafficserver,SolidWallOfCode/trafficserver,rpufky/trafficserver,SolidWallOfCode/trafficserver,duke8253/trafficserver,chenglongwei/trafficserver,rahmalik/trafficserver,taoyunxing/trafficserver,persiaAziz/trafficserver,taoyunxing/trafficserver,duke8253/trafficserver,clearswift/trafficserver,reveller/trafficserver,taoyunxing/trafficserver,dyrock/trafficserver,chenglongwei/trafficserver,clearswift/trafficserver,chitianhao/trafficserver,reveller/trafficserver,rahmalik/trafficserver,chenglongwei/trafficserver,clearswift/trafficserver,reveller/trafficserver,chenglongwei/trafficserver,PSUdaemon/trafficserver,vmamidi/trafficserver,SolidWallOfCode/trafficserver,duke8253/trafficserver,pbchou/trafficserver,reveller/trafficserver,chitianhao/trafficserver,dyrock/trafficserver,SolidWallOfCode/trafficserver,duke8253/trafficserver,chenglongwei/trafficserver,clearswift/trafficserver,davidbz/trafficserver,chitianhao/trafficserver,pbchou/trafficserver,reveller/trafficserver,PSUdaemon/trafficserver,bryancall/trafficserver,vmamidi/trafficserver,rpufky/trafficserver,reveller/trafficserver,rahmalik/trafficserver,PSUdaemon/trafficserver,persiaAziz/trafficserver,pbchou/trafficserver,rpufky/trafficserver,rahmalik/trafficserver,persiaAziz/trafficserver,chitianhao/trafficserver,vmamidi/trafficserver,rahmalik/trafficserver,vmamidi/trafficserver,dyrock/trafficserver,rpufky/trafficserver,persiaAziz/trafficserver,bryancall/trafficserver,SolidWallOfCode/trafficserver,davidbz/trafficserver,rahmalik/trafficserver,davidbz/trafficserver,reveller/trafficserver,rpufky/trafficserver,clearswift/trafficserver,PSUdaemon/trafficserver,duke8253/trafficserver,chenglongwei/trafficserver,PSUdaemon/trafficserver,chenglongwei/trafficserver,chenglongwei/trafficserver,pbchou/trafficserver,davidbz/trafficserver,PSUdaemon/trafficserver,duke8253/trafficserver,bryancall/trafficserver,vmamidi/trafficserver,bryancall/trafficserver,vmamidi/trafficserver,clearswift/trafficserver,taoyunxing/trafficserver,persiaAziz/trafficserver,pbchou/trafficserver,taoyunxing/trafficserver,persiaAziz/trafficserver,rahmalik/trafficserver,chitianhao/trafficserver,clearswift/trafficserver,rpufky/trafficserver,dyrock/trafficserver,pbchou/trafficserver,reveller/trafficserver,PSUdaemon/trafficserver,SolidWallOfCode/trafficserver,dyrock/trafficserver,clearswift/trafficserver,chitianhao/trafficserver,taoyunxing/trafficserver,SolidWallOfCode/trafficserver,bryancall/trafficserver,persiaAziz/trafficserver,rpufky/trafficserver,PSUdaemon/trafficserver,duke8253/trafficserver,davidbz/trafficserver,bryancall/trafficserver,rahmalik/trafficserver