- Part of #9486
- Building on top of initial work by @jdunkerley and finishing it
- Reverted the changes to the Postgres_Dialect from last Snowflake work and split the Snowflake_Dialect into a separate module.
- Moved from `rounding_decimal_places_not_allowed_for_floats` to `supports_float_round_decimal_places` (as too confusing).
- Added Snowflake_Dialect type.
- Extracted `Snowflake_Spec` into separate `Snowflake_Tests`
- It imports the common tests from `Table_Tests`.
- Some initial adaptations to make the snowflake dialect not-crash.
- Adding `Internals_Access` proxy to allow external implementations to access our internal data structures without directly exposing them to users. Users should not use these.
- Adding profiling of SQL to check performance.
