PWGUD: updates to upcRhoAnalysis.cxx (#7894)

* simplified phi calculation, changed axes for phi plots, added plots for cos(2phi)

* removed some unnecessary templating, added Run 2-like dynamic DCA cut

* add process function for MC

* added pT binning for mass distributions

* remove repeated calculation of common variables

* changed up folders in histo registry, added a few histos

* CLang formatting