Implementation of a page to quantify per-gene variation and explore the threshold on the metric of variation to get the desired set of highly variable features. Creates a page with a scatterplot of the variance of log-expression against the mean log-expression and a table with features and their metrics of variation. With shiny inputs you can color highlight the hvgs in dependency to the proportion and minimal threshold of the relevant variation metric. Also you can download the selcted hvgs or the entire variation metrics table.