Redundant browser extension install sidebar component

[bvizureanu]

Decide based on the browser I am using which "store" I should be redirected to.

Don't keep two extremely similar functionalities on the top of the COVID-19 related links

• a subtle hint can be added to have it clear that the extension is chromium based + firefox (some subtle minimalist icons maybe..)

This takes up a lot of space and I'd rather be seeing something more useful (especially if I am not using both browser at the same time - :P )