dealing with installonlies, we always need RPMPROB_FILTER_OLDPACKAGE (RhBug:1095580)

Related: RhBug:1061780 and commit 26cd7b8.
doc: cli_vs_yum: we do not promote installs to the obsoleting package. (RhBug:1096506)
lint: make dnf_pylint take '-s' that suppresses line/column numbers.
fix: 'dnf repo-pkgs' failures (RhBug:1092006)
doc: document --debugsolver.
Drop --debugrepodata and susetags generation with it.

Occupies code yet nobody uses it and --debugsolver supersedes it anyway.
replaced 'unicode' conversion functions with 'ucd' (RhBug:1095861)
takes non-ascii cmd line input (RhBug:1092777)
fixed rpmbuild warning of missing file