New Courseware Block: LTI, refs #2326

app/controllers/courseware/lti.php

lib/classes/JsonApi/RouteMap.php

lib/classes/JsonApi/Routes/Lti/Authority.php

lib/classes/JsonApi/Routes/Lti/LtiToolsIndex.php

lib/classes/JsonApi/Routes/Lti/LtiToolsShow.php

lib/classes/JsonApi/SchemaMap.php

lib/classes/JsonApi/Schemas/LtiTool.php

lib/models/Courseware/BlockTypes/BlockType.php

lib/models/Courseware/BlockTypes/Lti.json

lib/models/Courseware/BlockTypes/Lti.php

resources/assets/stylesheets/scss/courseware.scss

resources/vue/components/courseware/CoursewareLtiBlock.vue

resources/vue/components/courseware/container-components.js

resources/vue/courseware-index-app.js