Expose and document a simpler public API for simplify expressions

[alamb]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.
Similarly to #3708,

We programmatically create Exprs and would like to take advantage of the simplify + const evaluation code.

In IOx we have a SimplifyAdapter that does this https://github.com/influxdata/influxdb_iox/blob/alamb%2Fmass_upgrade/predicate/src/rpc_predicate.rs#L279 but it would be better to get this API more visible

Describe the solution you'd like
I think I would like a interface like:

/// Apply simplification and constant propagation to `expr` 
/// for example `X + (1 + 3)` is rewritten to `X + 4`
pub fn simplify_expr(expr: Expr, schema: &DfSchema, props: &ExecutionProps) -> Result<Expr> {
...
}

Describe alternatives you've considered
Can keep doing SimplifyAdapter type

Additional context
N/A