Feature request: Support ListenPort configuration Wireguard VPN connections

[AidanHarveyNelson]

What's the feature 🧐

Add capability to support setting static listener port when defining a Wireguard configuration.

As per the Wireguard man page https://manpages.debian.org/testing/wireguard-tools/wg.8.en.html this should be possible by allowing the configuration to set a ListenPort variable as part of the Interface configuration.

Extra information and references

• I have tried defining a conf file and setting a ListenPort variable and load it into the container as per https://github.com/qdm12/gluetun-wiki/blob/main/setup/providers/custom.md . The container loads successfully but a random port is still being used