For anything that is a list (temporal prop values and list props) we should add several list based functions e.g. len sum avg, min, max.

[shivamka1]

/// Effective result dtype for (agg, element PropType) as per semantic:
/// Len -> U64
/// Avg -> F64
/// Sum -> U64 (unsigned), I64 (signed), F64 (float)
/// Min/Max -> same as element type (numeric only)