[FEATURE] Make it possible for the extension to affect only certain parts of a website

[Ijee]

As it is it seems like you can only enable or disable the text effect on the whole page rather than
only on the parts that are actually text heavy. What I mean by that is to let me choose on a site to site basis or generally
what DOM elements and all children this extension will affect when enabling it.

For example if implemented I should be able to select the main and aside html tag in the settings.

Another possbility would be to automatically detect what parts of a site is text heavy and apply the effect automatically on those parts but that is most likely even worse to implement and more error prone.

I am not sure if this is technically possible as it would most likely change how the extension crawls the DOM
and sorry if my description of this feature has been discussed before or is poorly written.

I feel like with this feature I could focus a bit more on what I actually want to read and don't have to turn the extension on and off again everytime but that would still be an option of course. Having this effect on menu items for me is actually less readable than without the extension entirely.

[asieduernest12]

this is similar to #190