Allow adding another PM user to a project as a follower

Current behavior:

Currently, only the project/job owner can receive notifications of job (project) status changes.

Workaround:

Create a filter in project owner's email inbox to forward the email notifications about the status changes to the "follower(s)".

Requested behavior:

Add the option to add one or more PM users into a project as followers who would be able to receive notifications of job (project) status changes.

Use case:

It would allow for easier tracking of jobs and projects when the main PM in charge of a given project is off duty.

TMS: Project & job management