Enable SynBioHub to use other triplestores

[cjmyers]

It would be nice to support triplestores other than Virtuoso.

Some notes about other options are below:

• Parliament is roughly as scalable as Virtuoso.

• Parliament is less scalable than a few other single-machine triple stores, like AllegroGraph and StarDog, but not by a huge amount.

• Parliament falls far behind newer entrants that are explicitly cloud-based, like BlazeGraph and Anzo. However, these all come with some odd trade-offs that can be difficult to swallow in many use cases.

• Parliament’s query performance and standards compliance are quite a bit better than Virtuoso’s. In addition, you will find setup and administration of Parliament to be tremendously simpler.

• Parliament’s inference is much more performant than Virtuoso’s and AllegroGraph’s. However, its level of inference is low (RL), so if you want more sophisticated inference I would recommend StarDog.

• Parliament does not implement ACID transactions, so it is somewhat vulnerable to things like power failures. We have done a number of things to mitigate these risks, but we have not invested the time to make it truly ACID. If that’s something you need, then my recommendation would be StarDog.

[jamesamcl]

There's also BlazeGraph, and https://aws.amazon.com/neptune/