Allow for static text

Current the player provides options for the text to display on the player as follows:

• Filename
• Description
• Node/entity title

Sometimes, the role of the player is obvious from context.

1. If a view has a player on each row, and another column in the view already give a title, then the player doesn't need to repeat that. It could just say "Play".
2. If a content type has an audio field that represents some aspect of the corresponding node (e.g. for a bird node it could be the sound of the bird song), then the player text could just say "List to song"

You can do this now using the description, but only by manually setting the exact same description on every single instance.

In both cases, the requirement is to define some static text on the formatter settings that will be used for all instances. Patch coming up, thanks.