WL#14064: Deprecate INFORMATION_SCHEMA.TABLESPACES

The INFORMATION_SCHEMA.TABLESPACES table is unused, so it
should be deprecated. 

Functional requirements:
````````````````````````

 FR1: On running SELECT from INFORMATION_SCHEMA.TABLESPACES,
 a deprecation warning shall be sent to the client.

I. INTRODUCTION:
````````````````

 The INFORMATION_SCHEMA.TABLESPACES table is unused and not
 planned to be used by any supported storage engine.
 
 This WL aims to throw a deprecation warning to the client
 when they SELECT from INFORMATION_SCHEMA.TABLESPACES.


II. DESIGN:
```````````

 1. Changes to current behaviour:
 --------------------------------

 On running SELECT from INFORMATION_SCHEMA.TABLESPACES, a
 deprecation warning will be sent to the client specifying
 that the table is deprecated and will be removed in a
 future release.


 eg: mysql> SELECT * FROM INFORMATION_SCHEMA.TABLESPACES;
     Empty set, 1 warning (0.00 sec)

     mysql> show warnings\G
     *********************** 1. row ************************
       Level: Warning
        Code: 1681
     Message: 'INFORMATION_SCHEMA.TABLESPACES' is deprecated
     and will be removed in a future release.
     1 row in set (0.00 sec)


III. UPGRADE:
`````````````
 No impact on upgrade by this WL's changes.


IV. PERFORMANCE:
````````````````
 There shouldn't be any performance issues caused by this
 WL's changes.


V. DOCUMENTATION:
`````````````````
 Update to documentation should not be required. 
 Documentation for the INFORMATION_SCHEMA TABLESPACES table
 already states "This table is unused. It is deprecated and
 will be removed in a future MySQL release."