Webhook is called, whenever a CR is requested in a specific version.
This allows for a better updating path, as old CRs are still useable.

[conversion] Provide conversion java project:
- A webhook that offers endpoints for the three CRD types
- Is buildable as a runnable jar
- Contains Mappers from all supported versions to a hub

[common] Add Hub and previous version for all CRDs
- The hub is a superset of all values of a CRD across all versions
- Keep a copy of the old supported versions to transform back
- This is useful, as this way the the old operator still works
- Supported from these versions:
    - `AppDefintion.v1beta8`
    - `Session.v1beta6`
    - `Workspace.v1beta3`
- To showcase the functionality update CRDs to new version:
    - Move status like fields to status:
        - `Session.v1beta7`: Move `url`, `lastActivity` and `error` fields
        from the spec to the status.
        - `Workspace.v1beta4`: Move the `error` field from the spec to the status.
        Also add the `error` field to `Workspace.v1beta3` as it was missing

    - Remove `timeout.strategy` from AppDefinition
        - `AppDefinition.v1beta9`: Removed `timeout.strategy` and `timeout.limit`
        is now just `timeout`. This was done, as there is only one Strategy left.

[operator] Adjust operator so it works with the above changes.

[service] Adjust service so it works with the above changes.

[documentation] Add build command for `conversion-webhook`

[.github] Add ci for `conversion-webhook`
- Also fix publishing of new `next-version` (reusable typo)

Contributed on behalf of STMicroelectronics
Co-authored-by: Johannes Faltermeier <jfaltermeier@eclipsesource.com>

* add eclipse metadata to be consistent with other java components
* open all projects in Theia IDE with Java once to update settings

* add eclipse metadata to be consistent with other java components
* open all projects in Theia IDE with Java once to update settings

Update `v1beta8` references to `v1beta9`.
Fix `sessionSecret` in `SessionHub`.
Fix tests.
Use `org.jboss.logging.Logger` in conversion project.
Also log the endpoints that were triggered.

Fix minor issues in constructors.