add unitfile for ncm-cdispd, remove initscripts/chkconfig support

[stdweird]

Add unitfile for ncm-cdispd.

Possible issue: the configfile options "--quiet/-D" should not be set; and pidfile and logfile options are ignored

[jouvin]

@stdweird I open a PR on your PR to remove references to chkconfig that requires to define chkconfig as dependency for ncm-cdispd, as it is a source of problem on EL9. This breaks the compatibility with EL6 but it is also the case in cdp-listend (quattor/cdp-listend#33).

In addition to the potential chicken&egg problem with chkconfig packages if it is not installed first, these changes fix the boot ordering issue between ncm-cdispd and NetworkManager (see quattor/configuration-modules-core#1671). The new version has been tested successfully at IJCLab (EL9).

I let you fix the unit test problems that are not introduced by my changes.

[jouvin]

@stdweird please could you merge my PR to your branch so that we have a branch with everything. This is really required for EL9 support.

[ned21]

Not sure it's completely accurate but adding the backwards incompatible label to highlight in the release notes that this drops EL6 support.