Service Monitoring [Further plan][Draft]

[aceforeverd]

short term plan after #1048

• rewrite in go. easy to distribute, no run time deps

some dependent job

• openmldb docker image as a server, current openmldb image is a demo, better rename it
• docker-compose.yml or something similar to start clustered openmldb easily with docker

related but not depended

• disscussion: deprecate mon as service manager, there are modern ways

long term plans

• redesign metrics exposed by openmldb exporter
  • can design in the prometheus notation