WIP: Translations on Support Request App

( this is just started work, not to loose the state )

• translate in functional tests ( how to switch back to english in teardown etc ?) done in https://lab.nexedi.com/nexedi/erp5/merge_requests/1285 , the trick is to use language in url
• use consistent terms with erp5_crm ( for example Support request view uses "Support Type" / erp5_crm uses "Support Request Type" ) done in https://lab.nexedi.com/nexedi/erp5/merge_requests/1285
• translate front page graphs ( done in a customer project - ask @jerome or @gabriel )
• translate front page ( done a bit in https://lab.nexedi.com/nexedi/erp5/merge_requests/1285 and fully for a project - ask @jerome or @gabriel
• translate momentjs on the support request comment page
• there seem to be a double translation on frontpage listbox title (maybe there are others ?) done in done in https://lab.nexedi.com/nexedi/erp5/merge_requests/1285
• add a translation gadget ( can't we simplify this so that instead of defining the gadget URL we just define the URL of a json with translations ? ) done long time ago