It appears the interaction between Ronda Rousey and Stephanie McMahon at WrestleMania may have indeed been an angle to set something up for a future date, specifically a future WrestleMania.
Longtime wrestling journalist Dave Meltzer discussed the situation on his radio show, Wrestling Observer Radio with Bryan Alvarez what the WWE wants. What they want is something they've been pushing for since SummerSlam, where Rousey also visited the locker room and spoke with top officials. That idea is for a WrestleMania match with Stephanie McMahon.
There was speculation that it could be a mixed tag match, with The Rock and Triple H thrown in, but the current outlook is reportedly Ronda versus Stephanie. Obviously, the UFC and Dana White specifically, would have to approve of this match as Rousey is still under contract. It likely wouldn't be a dangerous match for Rousey to work, as she would likely go over, as outside celebrities always do in wrestling.
Still, she is one of, if not THE highest draw in the UFC and they'd understandably have concerns about Rousey competing in a WWE ring, where the benefits largely lie with the WWE and the risk lies all on the UFC. The WWE would have to throw something in that would tickle the UFC's funny bone.
Either way, we as fans are left hoping for Rousey to become the next dominant female in the WWE.