copr: implement search function

Signed-off-by: Igor Gnatenko <i.gnatenko.brain@gmail.com>
copr: Fix the playground upgrade command.

It should actually remove all old repos first and then fetch all available Playground repos.
remove dnf.yum.i18n imports.

the module was never in the API spec and no longer exists.
copr: get rid of dnf i18n imports

Ales do not want it there.
Replacing _() by identity
Once it will exists, I will
change it to something shared amongst all plugins.
copr: some python3 migration

to continue I need python3-urlgrabber which is not done yet.
See: https://bugzilla.redhat.com/show_bug.cgi?id=985288
copr: C: 33, 0: No space allowed before :
copr: W: 23, 0: Unused import gettext (unused-import)
copr: C:139, 0: Unnecessary parens after 'print' keyword (superfluous-parens)