Add functionality to pull memberships from a memberships service, if one is specified in the launch request.
Memberships is currently defined as an LTI extension and is implemented in several consumers as such. This client implementation will primarily target the basiclti4moodle service implemention and will also add support for a proposed change to the core Moodle LTI module (https://tracker.moodle.org/browse/MDL-41724).
The idea is to check for the 'ext_ims_lis_memberships_url' parameter in the launch, call the service and provision all the users, and groups if supplied, in the Sakai site. This will be advantageous for tools such as Signup where tutors may well want to arrange meetings in advance of users individually clicking through and showing up in Sakai. This behaviour will be off by default and enabled with a property.
A caveat is that the spec may change over time as LTI 2.0 solidifies. If so, this work will have to be updated.