Introduce marker size component

[Wumpf]

What

• Needed for Update all examples that use TimeSeriesScalar to use Scalar instead #5042

Allows to configure size again for points wiht the new PointSeries archetype.

Makes size of plot line and marker independent which is kinda neat :)

(Color is not independent, we'll want to solve this differently in the future in accordance to the model we're going with, but up for discussion obviously)

Checklist

• I have read and agree to Contributor Guide and the Code of Conduct
• I've included a screenshot or gif (if applicable)
• I have tested the web demo (if applicable):
  • Using newly built examples: app.rerun.io
  • Using examples from latest main build: app.rerun.io
  • Using full set of examples from nightly build: app.rerun.io
• The PR title and labels are set such as to maximize their usefulness for the next release's CHANGELOG

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[teh-cmc]

• Checked on web ✅