Foreman Maintain

Fixes #20870 - hammer ping check with default tag

Fixes #19715 - [Check] WARN if foreman-proxy is self-registered

Merge remote-tracking branch 'origin/master' into upgrade-workflow

Fixes #46 - isc dhcp configuration check

Move sync-plans checks to pre/post migrations

RFE #23 - Add new status [WARNING] - Check: is system self registered

RFE #16 - Delete invalid tasks

Fixes #19 - Handled sync plans before & after upgrade

With this commit, below changes included -
1. Two new checks
- Disable sync plans before upgrade
- Enable sync plans after upgrade which are disabled previously.

2. Created directory lib/foreman_maintain/storage in which...

Add tests for tasks paused check and additional procedures

Run confine against classes, not objects

This allows us to have multiple objects of the same procedure in the
system, differing in the constructor parameters. Useful for parametrized
procedures.