Ad-hoc email notification & templates

[gnyiri]

As far as I know there are two options for sending notifications from within the system:

1. implement a dedicated email handler, read the templates from the file system and send the emails
2. use status actions and setup the templates + events that will trigger email notifications

Both approaches require pre-defined templates stored on the file-system and if a template changes the backend needs to be restarted. Also, it is not possible (i didn' find) a way to setup the templates themselves from the frontend. That is, the User Officers do not have full control on managing the templates.

At ELI we would occasionally need to send 'ad-hoc' notifications to the PI-s for a given subset of proposals with a custom/temporary template. For such notifications we don't want the notification flag to be set. The idea is as follows:

1. user selects one or two proposals on the proposals page
2. user clicks on 'Send email' button
3. a dialog with a text area/listbox pops up
4. user selects the template to be used from a pre-defined set of available templates (listbox) OR enters a new template in the text area
5. user clicks on 'Send' and all the PI-s will be notified with the message according to the selected template

The recipients can also be configurable just like it is for the status actions.