this removes the old (unused) config for an angel system used during the
fridays for future camp 2020. Since it was configured "by hand" and not
in a declarative manner, and since there is now an actual module
`services.engelsystem` that we already use for the divoc it seems unlikely
that we will ever need the old config again.
From Nix's point of view, this commit is equivalent to doing nothing.
stuebinm
d7b70742fe