Some fixes coming from V9 revision 2be1dfc1ed7c9814cd3dbf4eb4cc95f842f738c2. The
purpose is to avoid to send emails in batch and to limitate automatic
subscription.
- add a context key to use the email queue for notifications linked
to allocations created in batch. This way emails will be send asynchronously
and will not create a deadlock when having a lot of allocations to process.
- also fixed a missing context in a browse