Set "AllowUserPorts: 80 443" as default in acng.conf

[reefland]

Since the "acng.conf" is not exposed externally nor changes persisted. Would like to set AllowUserPorts: 80 443 in order address a bug introduced in apt-cacher-ng 3.74:

https://bugs.launchpad.net/ubuntu/+source/apt-cacher-ng/+bug/1993026

This bug prevents https caching when using the "tell-me-what-you-need method" for Access to SSL/TLS remotes on client side configuration.

deb http://HTTPS///get.docker.com/ubuntu docker main
# If apt-cacher-ng is configured as proxy in APT, this makes it
# switch internally to https://get.docker.com/ubuntu
deb http://acnghost:3142/HTTPS///get.docker.com/ubuntu docker main
# Basically the same just with access to apt-cacher-ng through
# URL rewritting instead of setting http proxy.

#38 would help with this as well.