Refactor tenant database configuration to use dynamic config values

- Replace hardcoded database names (online_arrahn, master_krk, kaunterpkb)
  with configurable values across the codebase
- Rename tennant_master.php to tennant_database.php for clearer naming
- Update config keys: 'database' → 'master_db', add 'kaunter_db'
- Update env variables: TENNANT_MASTER_DB and TENNANT_KAUNTER_DB
- Modify Helper.php to use dynamic database references in
  getOnlineArrahnConnection(), getActiveCawanganDbConnection(),
  and getInactiveCawanganDbConnection() methods
- Update database JOIN queries in CustomerController and MarhunController
  to use config values instead of hardcoded database names
- Simplify migration logic by removing redundant hardcoded database checks
- Update debug messages in CawanganDebugConnections to show actual
  configured database name
- Update bootstrap/app.php to load tennant_database config

This change improves multi-environment flexibility and eliminates
environment-specific hardcoded values, making the application more
configurable for different deployment scenarios (KRK, KGMK, etc).

config/tennant_database.php

@@ -0,0 +1,6 @@
+<?php
+
+return [
+   'master_db' => env('TENNANT_MASTER_DB','online_arrahn'),
+   'kaunter_db' => env('TENNANT_KAUNTER_DB','kaunterpkb')
+];

config/tennant_master.php

@@ -1,5 +0,0 @@
-<?php
-
-return [
-   'database' => env('TENNANT_MASTER_DB','master_krk')
-];