Refactoring - renaming - fix wrong validation

Related issues

Acceptance criteria

• Implemented code changes don't diverge from the related issue.
• Documentation reflects the status quo after merge.
• Version number is incremented according to SemVer. (Snapshot versions are not merged/released.)
• Only released versions of dependencies are used (i.e. no snapshot versions).
• Pipeline still works.
• GitLab issue is up-to-date.

If necessary, the following sections have been updated:

• Swagger
• Readme.md
• Documentation

Proposed squash commit message

Refactoring - renaming - fix wrong validation

* Renaming to be consistent with _Consignee_ and _Sender_:
  * SIX:
    * `CarrierInformation`
        * `carrierName` to `carrierNameCompany`
        * `carrierPersonName` to `carrierNamePerson`
        * `carrierStreetName` to `carrierStreet`
  * SEVEN:
    * `SuccessiveCarriers` to `SuccessiveCarrierInformation`
* Refactoring:
  * SEVENTEEN:
    * Introduce class `CustomCharge` with attributes
      * `value: Float`,
      * `currency: String` and
      * `payer: PayerType`.
    * Replace type of attributes of `ToBePaidBy` with new type `CustomCharge`.

Co-authored-by: NAME <EMAIL>