[BUG] missing days with zero count in linechart and barchart

[sogo-on-github]

Describe the bug
unfortunately there is a missing option (!?) for displaying also days with a count of zero... currently they are just skipped in linechart and barchart

To Reproduce
Steps to reproduce the behavior:
create a line chart with "day" and days with count of zero
Expected behavior
show the line getting to zero or an empty bar but with no gap in the days on xaxis

Screenshots