* First cut image update for kubernetes support.
With this,
1) dockers dhcp_relay, lldp, pmon, radv, snmp, telemetry are enabled
for kube management
init_cfg.json configure set_owner as kube for these
2) Each docker's start.sh updated to call container_startup.py to register going up
As part of this call, it registers the current owner as local/kube and its version
The images are built with its version ingrained into image during build
3) Update all docker's bash script to call 'container start/stop/wait' instead of 'docker start/stop/wait'.
For all locally managed containers, it calls docker commands, hence no change for locally managed.
4) Introduced a new ctrmgrd service, that helps with transition between owners as kube & local and carry over any labels update from STATE-DB to API server
5) hostcfgd updated to handle owner change
6) Reboot scripts are updatd to tag kube running images as local, so upon reboot they run the same image.
7) Added kube_commands.py to handle all updates with Kubernetes API serrver -- dedicated for k8s interaction only.
**- Why I did it**
We were building a custom version of Supervisor because I had added patches to prevent hangs and crashes if the system clock ever rolled backward. Those changes were merged into the upstream Supervisor repo as of version 3.4.0 (http://supervisord.org/changes.html#id9), therefore, we should be able to simply install the vanilla package via pip. This will also allow us to easily move to Python 3, as Python 3 support was added in version 4.0.0.
**- How I did it**
- Remove Makefiles and patches for building supervisor package from source
- Install Python 3 supervisor package version 4.2.1 in Buster base container
- Also install Python 3 version of supervisord-dependent-startup in Buster base container
- Debian package installed binary in `/usr/bin/`, but pip package installs in `/usr/local/bin/`, so rather than update all absolute paths, I changed all references to simply call `supervisord` and let the system PATH find the executable to prevent future need for changes just in case we ever need to switch back to build a Debian package, then we won't need to modify these again.
- Install Python 2 supervisor package >= 3.4.0 in Stretch and Jessie base containers
The `-sv2` suffix was used to differentiate SNMP Dockers when we transitioned from "SONiCv1" to "SONiCv2", about four years ago. The old Docker materials were removed long ago; there is no need to keep this suffix. Removing it aligns the name with all the other Dockers.
Also edit Monit configuration to detect proper snmp-subagent command line in Buster, and make snmpd command line matching more robust.
