Add command to map external group to SCIM group in UAA.

[#74344702] https://www.pivotaltracker.com/story/show/74344702

Signed-off-by: Filip Hanik <fhanik@gopivotal.com>
Bump version to 3.1.0

Signed-off-by: Madhura Bhave <mbhave@gopivotal.com>
Add command to list group mappings

[74344702] https://www.pivotaltracker.com/story/show/74344702

Signed-off-by: Madhura Bhave <mbhave@gopivotal.com>
Add ability to unmap uaa scopes from external groups

Signed-off-by: Madhura Bhave <mbhave@gopivotal.com>