Use transifex for managing the translations

Author: nono

.tx/config

@@ -0,0 +1,8 @@
+[main]
+host = https://www.transifex.com
+
+[cozy-stack.global]
+file_filter = assets/locales/<lang>.po
+source_file = assets/locales/en.po
+source_lang = en
+type = PO

scripts/build.sh

@@ -176,6 +176,7 @@ do_deploy() {
 
 do_assets() {
 	clean_assets
+	tx pull -a || echo "Do you have configured transifex?"
 	prepare_assets
 	printf "executing go generate... "
 	go get -u github.com/rakyll/statik