README and docker compose improvement

[Taepper]

resolves #

Summary

improve README.md and remove superfluous database_config mount in the docker compose for ci.

The help text already mentioned that the database_config is relative to the input directory.:

         ConfigAttributeSpecification::createWithDefault(
            databaseConfigFileOptionKey(),
            ConfigValue::fromPath("database_config.yaml"),
            "File name of the file holding the database table configuration. Relative from "
            "input_directory."
         ),

Maybe this should have also been in the change-log?

PR Checklist

• All necessary documentation has been adapted or there is an issue to do so.
  - [ ] The implemented feature is covered by an appropriate test.

[github-actions]

This is a preview of the changelog of the next release. If this branch is not up-to-date with the current main branch, the changelog may not be accurate. Rebase your branch on the main branch to get the most accurate changelog.

Note that this might contain changes that are on main, but not yet released.

Changelog:

0.5.0 (2024-12-18)

⚠ BREAKING CHANGES

• new command line / config system

Features

• add materializationCutoff option (8920d5f)
• new command line / config system (2a29074), closes #633

Bug Fixes

• declare virtual constructor for abstract base class CustomSqlFunction (603ddf6)