CLC-4000 - Replace LTI Add People tool with modified Canvas Add People feature

https://jira.ets.berkeley.edu/jira/browse/CLC-4000
@redconfetti does it work without the `_blank`? Should still open in a new window because of the `outboundLinkDirective`.

https://github.com/ets-berkeley-edu/calcentral/blob/master/app/assets/javascripts/angular/directives/outboundLinkDirective.js