Add a few more hide-if-no-js classes

[johnbillion]

There are a few elements to which we could add the hide-if-no-js class, as their functionality or setting relies on JavaScript being available.

Patch. Hides the Press This link and two user settings which need JavaScript to function.

Does Press This actually need JS? Many probably selectively disable JavaScript at the domain level, rather than the browser level. I'm thinking that a browser bookmarklet may still work in the case of NoScript/AdBlock, etc.

The current implementation of Press This needs JS enabled for both domains, the WP install and the visited site. However if NoScript is used it's trivial to enable JS temporarily and use Press This.

Attached patch adds 'hide-if-no-js' class to the "Edit Image" button when viewing a media item, as image editing required JS.

Related: #19606, #19661

Choose from Media Library links

18900-header-bg.diff​ hides the 'Choose Image' button (from Media Library) on Custom Header & Custom Background pages. I left the direction label and added a "You need javascript to do this" message: ​http://cl.ly/image/3A3l2H420g40

Simplifies the UI, no empty space if no-js

18900-header-bg.2.diff​ Simplifies the UI, removes the entire <p> block if no-js and displays message instead: ​http://cl.ly/image/2a1C1u0L1J2A

Only introduce one new string, not two.

Combines with 18900.2.patch

#24321 was marked as a duplicate.