Feature/web preferences

[jmercouris]

I will need to test this within the context of Nyxt to see whether I can actually use the web-contents initarg in order to take a given view and change its preferences. I don't think we'll be able to. Probably we'll have to create a new view, with a new web-contents, and just append the previous web-preferences object.

[jmercouris]

After investigating more, I do not believe it is possible to create a new webContents object outside of a WebContentsView. Looking at the documentation:

 This class is not exported from the 'electron' module. It is only available as a return value of other methods in the Electron API.

https://www.electronjs.org/docs/latest/api/web-contents#class-webcontents

Therefore, I think this is the best solution we have to persist and mutate webPreferences. We'll just have to create new WebContentsViews to replace old ones whenever we make changes.

When we mutate a webPreferences object, it is unclear how we'll signal to the WebContentsView that it needs to be recreated. I almost believe that this should be the responsibility of the user of the WebContentsView, and not the responsibility of the class itself.