Garth could be opening a bar in Nashville...Craig Morgan has a memoir... Word on the streets of Nashville is that Garth Brooks may be the latest country star to open a venue on Music City's Lower Broadway. Garth could open up at the former home of Downtown Sporting Club and Paradise Park. Public records show that the 42,000-square-foot building sold in December for $48 million. If the venue works out, he'll join Luke Bryan, Miranda Lambert, Blake Shelton, Florida Georgia Line, Dierks…