Feature/migrate promise to plugin

Other tasks:

• wait for https://lab.nexedi.com/nexedi/slapos.core/merge_requests/64 to finish and https://lab.nexedi.com/nexedi/slapos/merge_requests/624 to avoid code duplication before doing duplicate test assertions for each SR
• support buildout.hash.cfg externally https://lab.nexedi.com/nexedi/slapos/merge_requests/631

Stacks to convert:

• lamp
• monitor
• caucase
• resilient

Stacks NOT TO convert:

• boinc
• hadoop
• lapp
• postgres

SRs to convert (with depending components):

• caddy-frontend
• erp5
• helloworld
• jupyter
• kvm
• monitor
• nextcloud, possibly needs changes to stack/lamp
• plantuml
• powerdns
• proftpd
• re6stnet
• seleniumserver
• slapos-master
• slaprunner
• turnserver

SR to convert which do not have SlapOS profile test:

• backupserver
• cloudooo
• erp5testnode
• gitlab
• grafana
• htmlvalidatorserver
• jstestnode
• nayuos
• theia

SR that WILL NOT be not be converted:

• boinc-client
• bonjourgrid-client
• bonjourgrid
• cdn-me
• davstorage
• dream
• etherpad-lite
• fluentd
• gateone
• html5ide
• postgres
• pureftpd
• redis-server
• slapos-in-partition
• test-slave-instance-deployment
• unstable/*

For each try to:

• assert that there is no need for etc/promise directory
  • if move out to etc/plugin
• check if it is ok to add tests for etc/plugin (follow caddy-frontend)

Additional tasks:

• use slapos.toolbox version with merged https://lab.nexedi.com/nexedi/slapos.toolbox/merge_requests/64

Notes:

• use monitor-promise-base and use git grep -l slapos.cookbook:promise.plugin to find needed replacements