Refactor DbClient integration tests

[romain-grecourt]

Description

Refactor DbClient integration tests.

• Use TestContainers, with oraclelinux based images
• Add one sub-module per database, add modules for h2, mysql, pgsql, oracle, mongo
• Add missing bom and all entry for helidon-integrations-db-pgsql

Refactor tests/integration/harness

• Removed all the suite support (potentially add back later in a different shape)
• Reworked HelidonProcessRunner into a more general ProcessRunner API

Documentation

None.

[Tomas-Kraus]

So first of all this changeset is something we needed since 4.0 was released. So it's great that we finally have it.
I just have a few concerns about it and it's maintenance which is mostly on me:

1. Do we really want to maintain such a huge amount of files for every single database vendor? I need to add few tests after fixing one issue in DbClient and it's terrible.
   Framework shall reduce coding, not multiple it.

2. Also running the tests without the suite is terribly slow. Especially with Oracle DB. Is there a way to resurrect at least some of the proposals I made in my own testing framework? It was pure junit based, with suites, SuiteResolver for Config, containers, DbClient. And it was designed to reduce code to be written, with pre-defined container setups for MySQL/Postgress/...
   I still have the whole thing available in my private repository.