Add support for SEMANTIC_VIEW table factor

[bombsimon]

Implements querying SEMANTIC_VIEW in Snowflake: https://docs.snowflake.com/en/sql-reference/constructs/semantic_view

SEMANTIC_VIEW(
  [<namespace>.]<semantic_view_name>
  [
    {
      METRICS <metric> [ , ... ] |
      FACTS <fact_expr>  [ , ... ]
    }
  ]
  [ DIMENSIONS <dimension_expr>  [ , ... ] ]
  [ WHERE <predicate> ]
)

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This change was more or less completely made with AI using Claude. I thought that's interesting to share both to ensure there's no non-AI policy I might violate, but also to showcase how quick it can be to extend functionality of this parser!

Other than some missing links, assumptions about METRICS and the usage of the discouraged dialect_of macro it more or less worked with a single prompt with some example queries and constraints as input! 🎉

[iffyio]

LGTM! Thanks @bombsimon!
cc @alamb