Log scaling ticks

[Yuri05]

Based on https://github.com/pchelle/Test-of-Pediatric-Qualification-Workflow/blob/main/Report.md

In the new reports, the axis in the log scale shows not the usual log ticks 10^N:

For comparison, the corresponding Matlab-Plot:

[pchelle]

{ggplot2} does not use a math format by default.
I noticed that the package {scales} (included in validR) with its function math_format is a really good solution for that.
https://scales.r-lib.org/

[pchelle]

Fixed by PR #201