Expose per-host pending update counts via the API

I work mainly with Zabbix monitoring, and I just got to know PatchMon this week — I think it's awesome. However, it still lacks an alerting system.

So I thought: why not integrate it with Zabbix? The idea is to make API requests from Zabbix using an HTTP Agent, create an LLD for each host registered in PatchMon, and then trigger alerts whenever a host has more than 'X' pending security updates.

However, the API currently only lists the hosts, without exposing their pending updates, or it provides only the total number of updates (/api/v1/gethomepage/stats), not per-host data. It would be really useful if the API could expose this information as well — for example, via endpoints like /api/v1/api/hosts/updates for total updates and /api/v1/api/hosts/sec-updates for security updates, or even by including fields for each update type directly in /api/v1/api/hosts, with per-host update counts.

Originally requested by flpems in Discord #ideas.