Update blog details media icon

- It was slightly too large before
Clean up

- Dropped ‘is’ from BOOLs

- Introduced enum for media type throughout

- Localized non-localized strings
Use thumbnail if available

- Previously narrowed to just Image. Allows for video if it was picked up when the user uploaded the video from the device

- Rename assets for the previous commit

Note that video thumbnails are not available through the API. It would be possible to add a thumbnail if the video is played.
Open media library for post media

- What it was before, until a merge blew it away

- Flow: Media icon in post -> Attached media (shows friendly message if no media attached yet) -> + button -> library to add existing media, or add more

- String updates
Remove old media handling files
Replace arrow icon with drag indicator
Remove blur view

- It didn’t seem to have as much of an effect in the later iOS 7 releases with the UIToolbar method. Now a translucent background
Clean up, spacing, renames
Authenticate private blog videos

- Only if needed

- Add load state and error state