Rudder

We have useless bootchecks in rudder that check for old migration:

- CheckApiTokenAutorizationKind: used in migration from 4.x to 4.3 to update api token format
- CheckCfengineSystemRuleTargets: used in migration to 4.3 to update server group request
- CheckNashornWarning: we don't use nashorn anymore in 7.0
- CheckRootRuleCategoryExport: used in migration to rudder 4.0
- CheckSystemGroups: ensure property about system groups changed in 2.10

Moreover, we want to better organize other bootcheck, splitting them in:

- consistency bootchecks (check consistency of dit, connections, etc)
- action bootchecks (do things based on the presence of files, create root api token)
- migration bootchecks (migrate things).
- onetimeinit (xml dump for config repo, init active technique lib, etc)