[8.x] Add better bitwise operators support

[Arzaroth]

Impetus

This addresses the problem mentioned in issue #40484

Changes

Since the bitwise operators are fundamentally different from other, in the sense that they do not produce boolean expression but integer based expressions, I elected to treat them differently from others.

Currently, both MySQL and SQLite support "implicit casting" of integer to boolean, but SQL Server and PostgreSQL do not.
The idea is to have a uniform behavior across all supported databases.

Previously this would yield a PDOException on PostgreSQL for instance :

$builder->select('*')->from('foo')->where('bar', '&', 1)->get(); // MySQL is cool with that, PostgreSQL looks upon you and declares that argument of WHERE must be type boolean, not type integer

The proposed implementation is database agnostic (as far as I'm aware at least). This is done by forcing a comparison, thus transforming the expression into a boolean one.

What next

This could open the door to support for basic arithmetic operators (e.g. +, -, etc...), although I would argue those appear even more elusively in WHERE clauses.

[Jubeki]

What is your reason for calling strtolower($operator)? In my opinion the operator has no lower or upper case.

Suggested change

	return in_array(strtolower($operator), $this->binaryOperators, true) ||
	in_array(strtolower($operator), $this->grammar->getBinaryOperators(), true);
	return in_array($operator, $this->binaryOperators, true) ||
	in_array($operator, $this->grammar->getBinaryOperators(), true);

[Arzaroth]

None in particular, I copied what I saw in the invalidOperator.