[Feature-request]: Refactor contract names to match contract file names

[aviggiano]

Describe the desired feature or improvement

This is a bit subjective, but I find it confusing:

import {PropertiesAsserts} from "@crytic/properties/contracts/util/PropertiesHelper.sol";

I propose a refactor so that the contract name matches the contract filename:

import {PropertiesAsserts} from "@crytic/properties/contracts/util/PropertiesAsserts.sol";