Support hostnames in UDP component as well as IP addresses

[Spamfast]

Component name

udp

Link to component documentation on our website

https://esphome.io/components/udp.html

Describe the enhancement

At present, the addresses key on the udp component accepts only dotted-quad IP addresses. It would be useful if it could accept an FQDN - or if the underlying stack honours DHCP option 119 an unqualified hostname.

Other components (if there are any) that talk to remote network devices could leverage the infrastructure put into place to implement this.

Use cases

I have a generic domain name syslog.lan on my network which points to the appropriate syslog server given who is making the DNS request. For connecting my ESPHome devices to my syslog infrastructure, it would be more manageable if I could use this instead of having to hard-code an address into the YAML and binary or resort to on_boot lambdas hacking into the component configuration.

It would also allow packet transport senders to identify their receivers by DNS name rather than hard-coded addresses which could change if reserved DHCP assigned after a network reconfiguration.

Anything else?

I know that the getaddrinfo() API works from lambdas on both the arduino & esp-idf frameworks for the esp32 platform so the base facility is available for these at least. Initial lookups could be triggered by wifi or ethernet interface bring up (i.e. upon address & DNS server discovery) and re-queried if the connection is lost and re-establsihed.

Given that mDNS is also a preferred lookup mechanism for ESPHome, then .local names should probably be supported via mDNS as well.