Add support for custom dnsmasq config and odhcp6c handler scripts
gluon-mesh-batman-adv: more initial -> invariant conversions
gluon-mesh-batman-adv: add DNS support
gluon-core: add support for NTP server configuration
gluon-autoupdater: add more models to README

This adds a list of known models to the readme.
gluon-core: move initial/020-wireless from generate to files
gluon-mesh-batman-adv: accept input on wan interface
gluon-luci-autoupdater: Catch up mirror support in gluon-autoupdater
gluon-autoupdater: Randomize mirror order

This way we have a kind of load balancing among the mirrors.