[Testing] Demonstrate CrateDB test layers with parameterization

[amotl]

About

GH-280 only demonstrates basic usage of CrateDB test layer variants. On a subsequent iteration, we may want to demonstrate how to parameterize them.

Requirements

The minimum set of parameters needed to cover common use cases in software testing.

• Software version of CrateDB (GA release, testing, nightly).
• TCP ports (HTTP and PG) CrateDB should be listening on.
• Heap size used by CrateDB, CRATE_HEAP_SIZE.
• Path to its data directory when aiming to expose it.

As an outlook...

• cr8's test layer is also capable of running clusters of multiple nodes, right? That is probably happening somewhere in crate-qa already? It should also be demonstrated in this context here.

References

Those are pointers to where parameterization is used, and not demonstrated here, yet.

• native/pytest: CrateLayer accepts settings, see pytest_crate/plugin.py.
• native/unittest: Dito, see crash::tests/test_integration.py.
• testcontainers/pytest: @pilosus added parameterization capabilities to cratedb-toolkit's CrateDBTestAdapter: Use testcontainers to improve platform coverage crash#408. Thanks.
• testcontainers/unittest: Dito.