Consider using browser default font

[Sebastiaan127001]

Is your feature request related to a problem? Please describe.
I'm always frustrated when Quality-time uses different fonts (at least three different fonts in v5.16), and the fonts used are in some cases less readable.

Describe the solution you'd like
I would like Quality-time to use the configured browser default font so that the end-user is in control. I believe this also will improve the accessibility of Quality-time for users can configure the font that suits them best.
As an example, Wikipedia also uses the browser default font.
If you change your browser's default font to an exotic one, you can see the result.

Good to know is that Quality-time uses the browser default font only in the toaster messages currently (v 5.16).