Develop ggplot2-implemented lollipop plots

[Kdreval]

Currently the prettylollipoplot uses g3viz under the hood to generate nice lollipop plots. However, the produced outputs are html-based, and the package itself has cBioPortal API dependency which in turn makes GAMBLR.viz very bulky, prone to installation errors, and requires very long installation time.
The ggplot2 on the other end is already a dependency and implementing the lollipop functionality through ggplot2 will address all of these issues.