MDEV-34716 Allow arbitrary options in CREATE SERVER

The existing syntax for CREATE SERVER

CREATE [OR REPLACE] SERVER [IF NOT EXISTS] server_name
    FOREIGN DATA WRAPPER wrapper_name
    OPTIONS (option [, option] ...)

option:
  { HOST character-literal
  | DATABASE character-literal
  | USER character-literal
  | PASSWORD character-literal
  | SOCKET character-literal
  | OWNER character-literal
  | PORT numeric-literal }

With this change we have:

option:
  { HOST character-literal
  | DATABASE character-literal
  | USER character-literal
  | PASSWORD character-literal
  | SOCKET character-literal
  | OWNER character-literal
  | PORT numeric-literal
  | PORT quoted-numerical-literal
  | identifier character-literal}

We store these options as a JSON field in the mysql.servers system
table. We retain the restriction that PORT needs to be a number, but
also allow it to be a quoted number, so that SHOW CREATE SERVER can be
used for dumping. Without an accompanied implementation of SHOW CREATE
SERVER, some mysqldump tests will fail. Therefore this commit should
be immediately followed by the one implementating SHOW CREATE SERVER,
with testing covering both.

mysql-test/suite/funcs_1/r/is_tables_mysql.result

@@ -515,7 +515,7 @@ TABLE_SCHEMA	mysql
 TABLE_NAME	servers
 TABLE_TYPE	BASE TABLE
 ENGINE	MYISAM_OR_MARIA
-VERSION	10
+VERSION	11
 ROW_FORMAT	DYNAMIC_OR_PAGE
 TABLE_ROWS	#TBLR#
 AVG_ROW_LENGTH	#ARL#