The plugin should require setting less roles for the lti instructor

[tibroc]

The documentation states that many roles should be set for the lti user:

studip-opencast-plugin/INSTALL.md

Line 27 in 701056c

lti.custom_roles=ROLE_STUDIO,ROLE_ADMIN_UI,ROLE_UI_EVENTS_DETAILS_COMMENTS_CREATE,ROLE_UI_EVENTS_DETAILS_COMMENTS_DELETE,ROLE_UI_EVENTS_DETAILS_COMMENTS_EDIT,ROLE_UI_EVENTS_DETAILS_COMMENTS_REPLY,ROLE_UI_EVENTS_DETAILS_COMMENTS_RESOLVE,ROLE_UI_EVENTS_DETAILS_COMMENTS_VIEW,ROLE_UI_EVENTS_DETAILS_MEDIA_VIEW,ROLE_UI_EVENTS_DETAILS_METADATA_EDIT,ROLE_UI_EVENTS_DETAILS_METADATA_VIEW,ROLE_UI_EVENTS_DETAILS_VIEW,ROLE_UI_EVENTS_EDITOR_EDIT,ROLE_UI_EVENTS_EDITOR_VIEW,ROLE_CAPTURE_AGENT

It should be sufficient to set ROLE_STUDIO,ROLE_CAPTURE_AGENT.

Related to #725

[tgloeggl]

Lars told me once, that ROLE_CAPTURE_AGENT might be to much permissions, because it would include ROLE_ADMIN. Could you shed some light on that? @lkiesow