This change removes the OpenDC Harness modules from the main repository.
We have made the decision to take a different direction regarding the
specification and execution of experiments. The design of the current
harness does not integrate well with the specification of experiments in
the web interface. The new version focuses on proper integration with
the web interface, as well as via the command line interface.

This change updates the Gradle build configuration to ensure that all
library modules (that will be published) use testing and are included in
coverage reports. This should ensure the public modules remain well
tested.

This change removes the opendc-platform module from the project. This
module represented a Java platform which was previously used for sharing
a set of dependency versions between subprojects. However, with the
version catalogue that was added by Gradle, we currently do not use the
platform anymore.

This change adds support for the Gradle version catalog feature in our
build configuration. This allows us to have a single file,
gradle/libs.versions.toml, which contains all the dependency versions
used in this project.

This change updates the build scripts to use type-safe project accessors
when specifying build dependencies between modules.

This change splits the OpenDC Experiment Harness into separate modules.
This prevents users from pulling in unnecessary dependencies when
depending on the harness API.