Don't ship unnecessary files

We are currently shipping files that are not needed on end-user's system. Fixing this would significantly reduce the size of freedombox.deb binary package. Ensure that these files are not installed with './setup.py install' and thus don't end up in .deb package. These files are:

• locale//.p0
• static/themes/default/FreedomBox-Identity-Manual.pdf
• static/themes/default/FreedomBox-Logo.7z
• static/themes/default/img/FreedomBox-logo-.* (some are needed)