Add check to reject incomplete LDAP data

See merge request !8

Respect spaces in ARGS passed to systemd unit

See merge request !7

Add python port

See merge request !6

Fix lqp and adapt to Python3

See merge request !4

checkiftest not, as it will print an error every time

lpadmincern time should be enable'able

See merge request !2

Resolves following problem that the time is currently impossible
to enable.

```
The unit files have no installation config (WantedBy, RequiredBy, Also, Alias
settings in the [Install] section, and DefaultInstance for template units).
This means they are not meant to be enabled using systemctl.
Possible reasons for having this kind of units are:
1) A unit may be statically enabled by being symlinked from another unit's
   .wants/ or .requires/ directory.
2) A unit's purpose may be to act as a helper for some other unit which has
   a requirement dependency on it.
3) A unit may be started when needed via activation (socket, path, timer,
   D-Bus, udev, scripted systemctl call, ...).
4) In case of template units, the unit is meant to be enabled with some
   instance name specified.
```

Use a new systemd timer on CentOS 8 and above

See merge request !1

Steve Traylen authored Dec 13, 2019 and Alex Iribarren committed Dec 13, 2019

The files

```
/etc/logrotate.d/lpadmincern
/etc/cron.daily/lpadmincern
```

are replaced with units

```
lpadmincern.service
lpadmincern.timer
```

Some of options in `/etc/sysconfig/lpadmincern` are
redundant now and comments have been added to that affect.

Changes apply to eight and newer only

* when 'update' is called, only update the printers that are currently
 defined locally; rather than processing ALL printers

* 'lpstat -p', which is used to determine if a printer is defined or not
 takes 1 second to finish on the version of cups provided on CentOS8.

* Without this fix, it would take ~900 seconds for a 'lpadmincern -u', which
 is defined in the post install script of the rpm