Project action "Mail template to PM"

A new project action.

• Name "Mail template to PM"
• Tooltip "Sends a mail to the PM, that is prepared to be send with some manually added information to the Client user, who ordered the project in translate5s client portal."
• Action does, what the tooltip says.
• The mail is in the GUI language of the client user
• A text template for the mail that defines the contents of that mail and what meta fields it should contain where can be overwritten in the client-specific folder in translate5s installation directory
• Implemented in core code