Enhancement: Set DPI size

[jokey2k]

On a 4K screen, this is not fun to read. Did set monitor to FullHD as workaround so far.

[topological-state]

in the file stskit/mplstyle/dark.mplstyle of the stskit distribution you can find a dpi setting:

figure.dpi: 100 # figure dots per inch

please play with it and let me know whether it works. i can then try to find an automated solution or implement a configuration option.