Add overlap operator for Postgres

[negezor]

Motivation

Add overlap operator for PostgreSQL in PgBinOper

anyrange && anyrange → boolean

Do the ranges overlap, that is, have any elements in common?

int8range(3,7) && int8range(4,12) → t

https://www.postgresql.org/docs/current/functions-range.html

Proposed Solutions

PgExpr::overlap(expr);

And

Expr::expr(...).binary(PgBinOper::Overlap, ...);

[nrskt]

I would like to take this issue. May I create a pull request?