TrinoDialect should set if it supports statement cache

[mbacovsky]

Hello,

Since SQLAlchemy 1.4.5 it is required from third party dialects to set whether they comply with statement cache with supports_statement_cache attribute. More details in the docs.

If the attribute is not set the warnings like

lib/python3.8/site-packages/sqlalchemy_trino/dialect.py:259: SAWarning: Dialect trino:rest will not make use of SQL compilation caching as it does not set the 'supports_statement_cache' attribute to ``True``. 
This can have significant performance implications including some performance degradations in comparison to prior SQLAlchemy versions.  
Dialect maintainers should seek to set this attribute to True after appropriate development and testing for SQLAlchemy 1.4 caching support.  
Alternatively, this attribute may be set to False which will disable this warning. (Background on this error at: https://sqlalche.me/e/14/cprf)

are raised.