SNMP Trap

**Describe the problem you have/What new integration you would like**

Ability to send events and sensor data to SNMP managers.

**Please describe your use case for this integration and alternatives you've tried:**

ESPHome is the best way to manage a ton of ESPs, and I want to use it to place environmental monitors in a non-Home Assistant environment with large-scale monitoring software like Zabbix. SNMP is a standard way of transmitting network and state data to logging servers.

**Additional context**

I am happy to work on this feature (though definitely over a long period of time)! I believe SNMP is simple to implement, and I am very sure it has been done on an ESP before. It is a UDP packet sent to a configured host.

No files, tests, or entry points are named. Start by researching ESPHome's integration architecture and the constraints of sending SNMP over UDP from ESP devices. Done means a defined implementation can send events and sensor data to configured SNMP managers, with its behavior and supported scope documented.

Written by the indexing model from the issue text.