Feat/31-ui-fuseki-status

[pogi7]

Checklist before submitting a merge request

• [x] I have reviewed CONTRIBUTING.md document
• [x] All commits have been signed-off for the Developer Certificate of Origin. See here.
• [x] I have added my contribution to CHANGELOG.md
• [x] I have documented my code in the OML Vision Docs

Description of contribution

Add ability to see the ping and load status of a RDF triple store.

closes https://github.com/opencaesar/oml-vision/issues/31

Testing performed

• [x] I have added unit tests to cover additional functionality

How to Test Expected functionality changes

OML Model:

1. You can use this OML model for testing https://github.com/pogi7/kepler16b-example
2. If not already done so, update the src/vision/config/sparqlConfig.json file to include a pingEndpoint. Here's an example:

   {
   "queryEndpoint": "http://localhost:3030/tutorial2-inf/sparql",
   "updateEndpoint": "http://localhost:3030/tutorial2-inf/update",
   "pingEndpoint": "http://localhost:3030/$/ping"
   }

3. Click the OML Vision eye icon
4. At first you will see a new window called RDF Triplestore Status. Both icons should be red.
5. Once the gradle tasks load, click on the Run startFuseki task in the Setup Tasks window.
6. The PING STATUS should turn green
7. At this point click on the Check if triplestore is loaded button in the RDF Triplestore Status window.
8. The LOAD STATUS should still be red. This is expected since we didn't load any data into the database yet.
9. From the terminal, run ./gradlew owlLoad
10. When it finishes click on the Check if triplestore is loaded button in the RDF Triplestore Status window.
11. The LOAD STATUS will now turn green indicating that the triple store has data.
12. Click on the Check if triplestore is loaded button in the RDF Triplestore Status window.
13. You will see a popup in the lower right saying that Triplestore has data!

Additional context