[NewFeature] Support ExternalCatalogResource to simplify external table manage operation.

[HappenLee]

Fix #4556

1. Add new Resource ExternalCatalogResource

create external resource "odbc"
properties
(
   "type" = "external_catalog", (required)
   "user" = "test",(required)
   "password" = "", (required)
   "host" = "192.168.0.1", (required)
   "port" = "8086", (required)
   "type" = "oracle" , (optinal,only odbc exteranl table use)
   "driver" = "Oracle 19 ODBC driver" (optional,only odbc exteranl table use)
)

2.After create ExternalCatalogResource, can create external table like:

CREATE TABLE `test_mysql` (
  `k1` tinyint(4) NOT NULL,
  `k2` smallint(6) NOT NULL,
  `k3` int(11) NOT NULL,
  `k4` bigint(20) NOT NULL,
  `k5` decimal(9,3) NOT NULL,
  `k6` char(5) NOT NULL,
  `k10` date DEFAULT NULL,
  `k11` datetime DEFAULT NULL,
  `k7` varchar(20) NOT NULL,
  `k8` double NOT NULL,
  `k9` float NOT NULL
) ENGINE=MYSQL
PROPERTIES (
"external_catalog_resource" = "odbc",
"database" = "test",
"table" = "test"
);

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[morningman]

The current hierarchy is:
Resource -> external_catalog -> odbc_catalog

But I think it can be simplified as:
Resource -> odbc_catalog

So the "type" is "odbc_catalog", and "odbc_type" is "mysql".

[morningman]

the following host, port maybe null. we need to check them or use getxxx() methods.

[morningman]

LGTM