Fix scaling/output issues for graphs

[alex-rowley]

Graph scalings not always optimal

Background

Under certain settings, some of the output graphs may appear squished/stretched versus the optimal sizing. This occurs due to the method of serialisation on the R end.

Task

This task/issue is to:

• Make sure that all of the graphs serliazed under the Robyn Run function are scaled/sized appropriately before being converted into image format and that this occurs under different settings
• Add examples into the python script of how to retrieve each of the graphs and save them to disk.