Deploy a hosted version of Sakai

**Part of https://github.com/hypothesis/lms/issues/362**

In order to be able to test future versions of the LMS app in Sakai, we need a hosted instance we can use. For the other LMSes we've been able to get hosted versions set up by the organization which develops the LMS (for example https://hypothesis.instructure.com). For Sakai it looks like such an option is not so easily available. There is a public ["nightly deployment"](https://qa12-mysql.nightly.sakaiproject.org/) of the project but it gets reset every day. We've also been given limited access to test Hypothesis in existing installations of Sakai at certain institutions. We can't test the site-wide functionality this way though.

Since Sakai is open source, an alternative is for us to host our own instance.

- [ ] Create a Dockerized version of Sakai 12 (the current stable release) that we can deploy to our infrastructure
- [ ] Re-configure security groups for Elasticsearch so that we can limit access to h and bouncer application instances, to prevent third party apps such as Sakai and Metabase accessing it
- [ ] Deploy a tiny MySQL DB for Sakai to use (v5.x, using the UTF-8 charset)
- [ ] Deploy the Dockerized version of Sakai to EB
- [ ] Install the production and QA Hypothesis LMS apps site-wide to the deployed Sakai instance
- [ ] Create a set of test assignments in a [Hypothesis 101 course](https://hypothes-is.slack.com/archives/CBN3DGW02/p1543933883049800) to match the other LMSes
- [ ] Update the ["LMS instances" Google doc](https://docs.google.com/document/d/1p7XiZclKWDlkOxlcuHXdkrsGtemGeR5gQiJ4qUq7o00/edit#heading=h.3ky6j74kcjf5) with usage information for the hosted version