better error messages

[nekopsykose]

this involves some difference in how we display it probably, since the idea is to not make them 'on the same line' to be more useful/informative to people as to what is actually wrong and how they could fix it

for example: SONAME: {dep} (unknown provider) is usually confusing because nobody can figure out why the provider is missing/unknown, or how to actually fix it, unless they know it's traced from things present in the buildroot. it could instead print:

  error: SONAME: libfoo.so.1 (unknown provider)
  libfoo.so.1 was not found installed in the buildroot to trace a dependency from.
  did you forget a makedepends= that provides it?

and that would already tell people 'probably forgot some makedepends that gives me that library'

or something roughly like that. it goes for a lot of kinds of errors currently, should collate a list here