Page: Volunteer Applications - Handling valid forms

[some-molasses]

When a student submits a valid volunteer application form, it is emailed to the relevant exec.

Blocked by #160.

Acceptance criteria:

• When the user submits an application form successfully, an email is sent to the relevant exec with the following details:
  • Subject: "Volunteer Application - {Exec type (e.g. VPO)} - {Role}
  • Body: The contents of the form
• Note: nodemailer has already been set up to send emails for the Contact Us form - it hopefully will be relatively simple to reuse here