Update to Exceptions: add codes, update phpunit tests

DB Class throws Exception if on init it fails to connect to the DB,
will not throw Exception if failed connection during execution but
will do the normal retry and soft failure run
DB\ArrayIO will throw Exception on missing table array and table name

All Exceptions have a code set

www/lib/CoreLibs/DB/IO.php

@@ -414,6 +414,7 @@ class IO
 	 * phpcs:ignore
 	 * @param array{db_name:string,db_user:string,db_pass:string,db_host:string,db_port:int,db_schema:string,db_encoding:string,db_type:string,db_ssl:string,db_convert_type?:string[]} $db_config DB configuration array
 	 * @param \CoreLibs\Logging\Logging $log Logging class
+	 * @throws \RuntimeException If no DB connection can be established on launch
 	 */
 	public function __construct(
 		array $db_config,
@@ -492,6 +493,7 @@ class IO
 		if (!$this->__connectToDB()) {
 			$this->__dbError(16);
 			$this->db_connection_closed = true;
+			throw new \RuntimeException('INIT: No DB Handler found / connect or reconnect failed', 16);
 		}
 	}
 
@@ -974,9 +976,9 @@ class IO
 	/**
 	 * write an error
 	 *
-	 * @param integer $error_id            Any Error ID, used in debug message string
+	 * @param integer $error_id           Any Error ID, used in debug message string
 	 * @param \PgSql\Result|false $cursor Optional cursor, passed on to preprocessor
-	 * @param string $msg                  optional message added to debug
+	 * @param string $msg                 optional message added to debug
 	 * @return void
 	 */
 	protected function __dbError(