Add snowflake dynamic table parsing

[romanoff]

Add snowflake dynamic table parsing. Reference to spec:
https://docs.snowflake.com/en/sql-reference/sql/alter-dynamic-table

Example of sql:

ALTER DYNAMIC TABLE MY_DYNAMIC_TABLE REFRESH;
ALTER DYNAMIC TABLE MY_DYNAMIC_TABLE SUSPEND;
ALTER DYNAMIC TABLE MY_DYNAMIC_TABLE RESUME;

[iffyio]

Thanks @romanoff! The changes look reasonable to me, left a comment

[iffyio]

Can we replace the iceberg:bool field with an enum instead? thinking so that we don't accumulate booleans over time (e.g. its not clear or enforceable that iceberg and dynamic are mutually exclusive).

e.g.

enum AlterTableType {
    Iceberg
    Dynamic
}
Statement::AlterTable { table_type: AlterTableType }