Change client-facing usages of "Bookmark" to "Favorite"

File Browser has a section marked with a heading of "Favorites", but all text for the operations on these items refers to them as "bookmarks". This patch gives us consistent usage of "favorite" for these.

This is an alternative to the one-line patch D10262 that changes the section heading to "Bookmarks". I still prefer the "bookmark" term over "favorite" as it is a more platform- and application-agnostic terms for these items. But even if we don't change it, using both is confusing. Using both mixes two metaphors at once like "bookmarking a favorite" or "favoriting a bookmark".

Currently when there are no favorites we show a big button to "Add Bookmark"

Hovering over the "+" to add a new one and the tooltip says "Add a Bookmark". You also "Remove Bookmark", "Move Bookmark", or select "Delete all invalid bookmarks" from the "Bookmarks Specials" menu.

So this just makes all these use "favorite".