- Use the VeroSubscriptionService as a pure communication service
- Do not contaminate the VeroSubscriptionService with holding data

- Verification is task of the common sanitizer
- Remove unnecessary AlertDialog

This reverts commit 93e62a4a.
Teststudio does not accept verona 4 specification data

Use verona-module-metadata.json to define json meta data in html header

Check whether `unitDefinition` or `unitStateDataType` are undefined is
done within the verify methods

* Define data version types data versions for `unitDefinition` and
`unitState` in meta tag of index.html
* Separate `MetaDataService` from `VeronaPostService`
* Extend `MetaDataService` to verify data versions of `unitDefinition` and
`unitState`