Add new geoms for Likert graphs etc

[rdstern]

We currently use the sjplot package for Likert graphs. The ggstats package is much more recent and now has a number of geoms added for those types of graph. I suggest we could move to that package and also those geoms. Maybe we could start by adding the geoms from Version 0.7.0 of the package. There are about 10 geoms and I suggest they will also make it simpler to add labels and percentages to the graphs, i.e. to improve our bar chart dialog. I think 0.8 is imminent and will add another 3 geoms too.

@N-thony I suggest @MeSophie has become pretty good at adding geoms. This work should also involve others in the checking, maybe @fran2or and/or @jkmusyoka