Use Testcontainers instead of custom CrateDB integration test helper

[amotl]

Hi there,

the BaseIntegrationTest.java currently uses io.crate.testing.CrateTestCluster and io.crate.testing.CrateTestServer from CrateDB Java Testing Classes. If it is capable enough to replace this layer, we could now use Testcontainers for Java » CrateDB support, thanks to @matriv's contribution https://github.com/testcontainers/testcontainers-java/pull/6790, which has been released yesterday.

With kind regards, Andreas.

[amotl]

We just added some blueprints how to use Testcontainers for Java with CrateDB.

• https://github.com/crate/cratedb-examples/pull/54
• https://github.com/crate/cratedb-examples/pull/59