Allow for customization of email subject/title

[tempsaint]

Currently, the emails that are sent to bmlt-workflow administrators has a subject of

[bmlt-workflow] Modify Meeting request received - [field:service-body-name] - Change ID #[field:id]

(I'm guessing at the field names).

It would be very helpful if we could customize the subject/title, or at least change out the service-body-name for meeting-name. There are times when we might need to search through emails for the specific meeting request or times when we might need to contact the submitter on their form submissions and forwarding the email and having it include the meeting name would be very helpful.

Upon more reflection... it would be very helpful to us to maybe customize the entire email body. For all emails that get sent out.