VGalaxies

close by #2424 and #2431

NOTE: the core tests of hstore expect the following tests to fail: ```text [INFO] Results: [INFO] Error: Failures: Error: EdgeCoreTest.testScanEdgeInPaging:5214 expected: but was: Error: MultiGraphsTest.testCopySchemaWithMultiGraphs:121 Error: VertexCoreTest.testAddOlapRangeAndOlapSecondaryProperties:2491 expected: but was:...

@imbajin Is anyone currently working on improving the Edge API? If not, please assign it to me.

merge directly into the master branch after #2498...

Temporarily ignore the above failures: ```java // FIXME: skip this test for hstore Assume.assumeTrue("skip this test for hstore", Objects.equals("hstore", System.getProperty("backend"))); ```

@sheli00 could follow up on this issue~

After inspection, only the hstore API test `testMetricsBackend(org.apache.hugegraph.api.MetricsApiTest)` has not passed. The reason is that the hstore backend has not set up the corresponding metrics. Considering that the PD metrics...

@sheli00 can participate in the subsequent adaptation of PD (hstore) metrics~