Add `Bankverbindung` and `Erreichbarkeit` COM Objects

[hamidhajiparvaneh]

Overview:

This task involves adding the Bankverbindung and Erreichbarkeit communication (COM) objects to the project. These changes are required for handling PARTIN messages and are detailed in the following PR:
BO4E-dotnet PR 466.

Additional information regarding the MIG and AHB specifications can be found in the BDEW files:

• BDEW MIG Document
• BDEW AHB Document

Changes Required:

1. Add Bankverbindung COM Object:

   • Implement the Bankverbindung object, including all required properties and structure as defined in PR 466.

2. Add Erreichbarkeit COM Object:

   • Implement the Erreichbarkeit object, as described in the same PR, including relevant properties and usage.

3. ** Other Geschaeftspartner changes.

Acceptance Criteria:

• Both Bankverbindung and Erreichbarkeit objects are correctly implemented as per the changes in PR 466.
• The objects follow the necessary structure for handling PARTIN messages as defined in the MIG and AHB documents.
• Unit tests are provided or updated to ensure correct implementation.