Add native charting to the engine

Task description

Read the chart definitions from LibChart and build a suitable dataset for the charts defined in there. In the simplest case, this can be implemented using similiar techiques used in the plattform, namely a set of expressions and some vodoo.

Requirements

This task depends on the chart definitions and chart backends provided by LibCharts.

Solution approach

A clean implementation would use the database interfaces defined by LibFormula to build the chart data and/or would treat charts as subreports which produce a single image.