More Snowflake work

project.clj

src/metabase/driver.clj

src/metabase/driver/generic_sql.clj

src/metabase/driver/generic_sql/query_processor.clj

src/metabase/driver/mysql.clj

src/metabase/driver/snowflake.clj

src/metabase/query_processor.clj

src/metabase/query_processor/middleware/parameters/sql.clj

src/metabase/query_processor/middleware/resolve_database.clj

src/metabase/query_processor/store.clj

test/metabase/driver/generic_sql_test.clj

...tabase/query_processor/middleware/parameters/sql_test.clj

test/metabase/query_processor_test/expressions_test.clj

test/metabase/query_processor_test/nested_queries_test.clj

test/metabase/test/data/generic_sql.clj

test/metabase/test/data/snowflake.clj