Switch unit testing to use a local docker image

[cjmyers]

Following the testing scheme for SBH, pull a local docker instance for local unit testing:

https://github.com/SynBioHub/synbiohub/tree/master/tests

[tcmitchell]

In addition to the synbiohub tests cited above:

• Work with @jvscholz when the time comes
• See https://github.com/SynBioHub/synbiohub-docker for the docker-compose files
• See https://synbiohub.github.io/api-docs/#installation for info launching

[tcmitchell]

I can bring up a SynBioHub instance for testing on an Ubuntu host as follows:

git clone https://github.com/synbiohub/synbiohub-docker
docker-compose -f ./synbiohub-docker/docker-compose.yml up -d

This gives us an unconfigured SynBioHub running at port 7777. Not sure how to configure SynBioHub, and it redirects to the setup page when PartShop.pull is invoked. So we'll need to somehow provide it with a configuration, or otherwise get it past this setup requirement.

[bbartley]

The plan for now is to table this for pySBOL2, but implement the Docker-based SBH testing for pySBOL3 and later back-port this solution to pySBOL2

[jakebeal]

Note that this is now a bit more pressing, since the prior Utah instance has gone down, per #390