[OPS][keepstore][puppet] migrate all keepstores configuration to systemd unit + config file
|Velocity based estimate||-|
- create config file for keepstore (default location: /etc/arvados/keepstore/keepstore.yml make sure there is no lingering config elsewhere)
- have the same parameters as the current keepstore under runit
- don't use exec() for restarting the service use puppet's systemd service
- make sure the config file is a unit.
- make sure to have a restart-obsessively parameter for systemd definition (see 273a233818ae39e843fab0276f9e381da6645d28)
once everything is tested
- remove runit
- remove all legacy distros regard this.
- review how we're packaging keepstore deb package to see if anything can be improved