RFC: Secrets for locations

[noxilixon]

As maintainer I want to store some informations related to an location, that only I and other maintainers could read. This would be useful for personal contacts, contract related data and other special notes that should not be public.

As we try to create a config file that represents all relevant data and want to move content from the wiki into that file, this is the place where this secret should be stored. This could also make the extra private repo that is used for gateway documentation obsolete, and make it clear for everyone where to find location related informations.

We already use ssh keys to authenticated as maintainers, so those could also be used to protect/encrypt the secrets?

Also the passwords for router and private-dhcp could be stored that way, making it possible to set it during build.