Add DBAPI warnings on corresponding events

[artembo]

DBAPI standard requires raising warnings when corresponding event is triggered.

Add missing warning messages (if feature is implemented):

• Warning Message: "DB-API extension cursor.rownumber used"
• Warning Message: "DB-API extension connection.<exception> used"
• Warning Message: "DB-API extension cursor.connection used"
• Warning Message: "DB-API extension cursor.scroll() used"
• Warning Message: "DB-API extension cursor.messages used"
• Warning Message: "DB-API extension cursor.next() used"
• Warning Message: "DB-API extension cursor.lastrowid used"
• Warning Message: "DB-API extension cursor.__iter__() used"
• Warning Message: "DB-API extension .errorhandler used"

[Totktonada]

Currently those ones are implemented:

• "DB-API extension connection.<exception> used"
• "DB-API extension cursor.lastrowid used"

Let's add warnings for them so.

See https://github.com/tarantool/tarantool-python/wiki/PEP-249-Database-API#extensions-defined-in-pep-249.