Add support for hostgroup.*

[Spartan0nix]

https://www.zabbix.com/documentation/6.0/en/manual/api/reference/hostgroup

• [x] hostgroup.create - creating new host groups
• [x] hostgroup.delete - deleting host groups
• [x] hostgroup.get - retrieving host groups
• [x] hostgroup.massadd - adding related objects to host groups
• [x] hostgroup.massremove - removing related objects from host groups
• [x] hostgroup.massupdate - replacing or removing related objects from host groups
• [x] hostgroup.update - updating host groups