Improve display of user-controlled text in Right-To-Left (RTL) languages
by applying the `dir="auto"` attribute to:

 - Input fields (annotation body editor, search bar)
 - The rendered annotation body's container element
 - The rendered annotation quote (ie. the `<blockquote>` element)

This will cause these elements to switch to their "base" direction for
text layout [1] to RTL or LTR automatically depending on the content
[2].

Fixes https://github.com/hypothesis/lms/issues/1372

[1] https://www.w3.org/International/articles/inline-bidi-markup/uba-basics
[2] https://www.w3.org/International/questions/qa-html-dir