Add the "asset viewer" page

I like how it's done in uBO, you can inspect the contents of any filter if you click on its name.

Let's add a "View" icon to the filters list: https://uploads.adguard.com/up04_sw55y_AdGuard_Settings.png

That will open a new page with an asset viewer. Full-screen ace editor with a search string (read-only) (disable word-wrap for it).