Add template group creation

[pederhan]

This PR introduces the ability to automatically create template groups for all managed host groups. Two new configuration options have been introduced to facilitate this:

[zabbix]
create_templategroups = false
templategroup_prefix = "Templates-"

On Zabbix <6.2, this feature will create the template groups as host groups instead.

The feature is disabled by default.

Version Checks

The BaseProcess class now fetches the Zabbix API version (always matches the Zabbix Server version) on instantiation and stores it in the attribute self.zabbix_version, which allows each process to perform version checks without having to add boilerplate code for fetching and parsing version numbers first. The version is stored as a packaging.version.Version object.

Comparing version numbers should be done on the release portion of the version name against a tuple of major, minor, micro (patch) versions, i.e.:

if self.zabbix_version.release >= (6, 2, 0): ...

And not Version objects against each other:

if self.zabbix_version >= Version("6.2.0"): ...

The main difference is that comparing releases allows for using alpha, beta and rc versions of Zabbix with ZAC. If we compared two Version objects against each other, the application would assume certain features are not available when running these pre-release versions:

>>> Version("6.2.0alpha1") >= Version("6.2.0") # fails to detect version 6.2
False
>>> Version("6.2.0alpha1").release >= (6, 2, 0) # correctly detects 6.2
True

Individual version number components can be accessed via attributes:

if self.zabbix_version.major >= 1: ...
if self.zabbix_version.minor >= 2: ...
if self.zabbix_version.micro >= 3: ...