engine: Cast rule more correct impl (cast -> to_*)

[DanCodedThis]

Right now, the cast rule is done as a Logical AnalyzerRule, but it may be done as any of the following (decide which is more correct):

• As is
• Logical OptimizerRule
• Physical rules
• sql_cast_to_expr
• TreeNodeRewriter
• Some other way (Change the logical expression itself in the planner?)