pidgin/pidgin

Move PurpleChatUser to it's own file and fix a few issues with the docs and translations

Move PurpleChatUser to its own file. Also fixed po/POTFILES.in

Testing Done:
Compiled and ran. ChatUser flags are not displayed but they also are not displayed on default right now either.

Reviewed at https://reviews.imfreedom.org/r/78/
pidgin3_xml = configure_file(
input : 'pidgin3.xml.in',
output : 'pidgin3.xml',
configuration : version_conf,
install : true,
install_dir : join_paths(get_option('datadir'), 'glade', 'catalogs'))