Simplify the individual form providers by always running reconfigure. This
also commits all UCI packages, so we can remove all tracking of UCI
sections from the wizard code.
Instead of returning a list of packages to commit, the providers just
save their settings directly. Explicit runs of upgrade scripts are
removed, as they are now run by reconfigure.
optional = true does not make sense without a datatype. When no datatype is
set, the empty string will be a valid value, so data is never unset in the
write function. Restore the minlength(1) datatype so the contact setting is
deleted as intended when no value is provided.
* do not allow to obligatorily require contact information
* add remark that the data is provided voluntarily
* mention how to delete the data
* be very clear about the fact that the data being entered is public and
can be downloaded and processed by anyone.
