Refactor termination and rental object entities

- Removed the "Kündigungen" field from the German and English rental object JSON files.
- Updated the termination JSON files to reflect new field names and structure, including renaming "kuendigungsart" to "beendigungsTatbestand" and "kuendigungsgrund" to "kuendigungsgrund" with updated options.
- Deleted the old "CKuendigung" entity definition and related metadata, consolidating functionality into "CKndigung".
- Adjusted the service logic to accommodate the new structure, ensuring proper linking of landlords and tenants.
- Updated dynamic visibility logic for fields based on conditions related to termination reasons and delivery methods.
- Cleaned up metadata definitions for both termination and rental object entities, removing unnecessary relationships and fields.
- Incremented cache and microtime values in the configuration file.

custom/Espo/Custom/Resources/metadata/scopes/CKuendigung.json

@@ -1,11 +0,0 @@
-{
-    "entity": true,
-    "layouts": true,
-    "tab": true,
-    "acl": true,
-    "customizable": true,
-    "type": "BasePlus",
-    "module": "Custom",
-    "object": true,
-    "isCustom": true
-}