Cohort auto roles management

This plugin is based on the core tool_cohortroles plugin and allows the selection of a role rather than an individual to assign a manager/mentor/parent to a user.

If a user is assigned the selected role at any level - (site/course/category etc) they will be assigned as the mentor/manager/parent to all users within the cohorts selected they are also a member of.

Example:

• Cohort "Engineering" has the users, "John, Mary, Steven, George"
• Cohort "6th Floor" has the users "John, David, Simon"
• John is enrolled in course 1 with the custom role "Support"
• David is assigned the custom role "support" at the site-level.
• A Parent/Mentor/manager role has been created in the system to allow user-level role assignments - see:https://docs.moodle.org/en/Parent_role
• The cohortautoroles plugin is configured to find all users in the "support" role, assign them to the parent/manger/mentor role.

John will be automatically assigned as the mentor to "Mary, Steven, George, David, Simon" 
David will be automatically assigned as the mentor to "John, Simon"

NOTE: Mentors will only be assigned if they are also a member of the cohort as well.