medkit-initial-config: add new package

The idea of this package is to allow users that do not have ethernet
port to configure router anyway. Usage is to place configure file
alongside the medkit and do medkit reflash. This wipes and updates
current installation (hopefully to latest version as user should always
download latest one) and on first boot (detected using schnapps as there
are no snapshots in such case) script from this package locates config
the same way as in rescue is medkit detected. Configuration is read and
applied to system. That is even before web server or even network
interface is started so it makes router much secure on first boot.