Email from address in application results email

When submitting a job application, the email that is sent to the HR person shows from the site default email address. This is fine if the user's email address is either:
A) Included in the email body for the HR person's reference, and/or
B) Set as the reply-to in the email headers

Leaving the from as the site default both helps and hurts spam prevention efforts. On the one hand, it makes it easier to whitelist the site email address that all of the applications come from, but on the other hand it makes it more likely that automated spam checkers will blacklist or black score emails from that address in the first place.

Steps to reproduce:
1. Set site default email address in /admin/settings/site-information to "siteinfo@example.com"
2. Create and/or log in as a user who's email address is "thisuser@thatdomain.com"
3. Create a job posting with Email field set to "youremail@yourdomain.com"
4. Submit an application
5. View email sent to "youremail@yourdomain.com"

Actual Behavior:
1. From is set to "siteinfo@example.com"
2. The return path is set to the sendmail default.
3. No other user information is prepended to the message

Requested Behavior
1. From is set to "thisuser@thatdomain.com", and/or
2. Return path in headers set to "thisuser@thatdomain.com"
3. Basic user information (username, first name, last name, and/or user email) prepended to the message