Make default scatterplot markersize smaller

[bednarsky]

• In my opinion the markers are too large, even for relatively few datapoints (even worse for more datapoints)
• For metadata plots one cannot nicely see how diverse clouds of data are since they are overlapping too much
• For final plotting, one has to adapt anyways, but it might be more useful to have them err for the too small side, so that information can be extracted for exploratory analysis
• Any strong advantage to make them this big?
• Example:

[sreichl]

this is customizable in the config. whats your config?

[bednarsky]

I used the default size=1; alpha=1, but I am suggesting to make a better default! Just playing around with it a bit to see what would make sense

[sreichl]

for scRNA-seq we could recommend in the docs 0.1, but for anything else 1 is mostly fine.