CYB-129 The 3 LTI Tools (PointsConfiguration, Gallery, and Leaderboard) ...

* adds thor tasks for each individually and one for all, to embed them in Canvas

```shell
    The ../config/.env_conf.yml file MUST have a new line added, so that Canvas can
    call back to the LTI tool to get the XML needed to make the configuration      
    the 'app' section for each Rails environment must have the 'lti_base_url' key 
    set to the location of the LTI app (DataCultures app), with trailing slash 
    (see the example file edited here)
```
[CYB-129 The 3 LTI Tools (PointsConfiguration, Gallery, and Leaderboard) should self-embed in Canvas](https://jira.ets.berkeley.edu/jira/browse/CYB-129)