Indicate if an app is translated in the user's locale in the Software Centre

Software Center should indicate whether software is translated for example by including a small flag icon. This way non-English-speaking users can see if the application is available in their local language when it contains a translated package description. Otherwise, translated package descriptions might mislead the user to believe the application is available in his/her local language.

http://brainstorm.ubuntu.com/idea/27948/

See also bug 706571.

Some use cases this would fix:

 a) non-english user clicks on a program name to see more info, sees
 the description in English and assumes the program is not translated
 and therefore doesn't install it, even though it might be translated
 into his native tongue.

 b) non-english user finds a program with a translated description,
 installs it only to find out the program itself is not translated and
 is therefore no use to him/her.

 c) user wants to install a music player in his native language. When
 searching for "music player" in the software center 10 hits appear but
 the user cannot filter the programs translated into his native tongue
 and therefore has to use trial and error.

 d) a one line description (po-app-install data) is translated, but
 description (ddtp-ubuntu) is not or vice versa. User is just confused.