[Feat]: Implement font-size to be configurable for Markdown, globally across the App

[adnanqaops]

Is your feature request related to a problem? Please describe.
We had a query from a User where the User needed to update the font-size of a Markdown column type in Table component. As, we should not have a textSize property on a Markdown. So, we need to provide a feature where

• There should be a "font-base-size" setting/variable
• It should impact all the Markdown across the App, globally

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