Introduce a new proboctl Cobra CLI for Probo instance management
that connects directly to PostgreSQL. Move the standalone
common-third-parties-import and common-tracker-patterns-import
commands into proboctl as `proboctl seed common-third-parties`
and `proboctl seed common-tracker-patterns`, replacing flag-based
PG connection with a shared factory pattern.
Signed-off-by: Émile Ré <emile@probo.com>