make base test suites available in released package

[martriay]

since users are responsible for manually exposing all the methods of libraries such as ERC20, ERC721, etc., it could be useful to make our base test suites like Ownable, ERC20, or ERC721 available for them to check their implementations.

this could be either as a separate package or in the same one as the contracts library.

[ericnordelo]

Maybe it is worth waiting for the migration to snforge test suite before addressing this, if we decide it is time to do such migration.

[ericnordelo]

Making the whole test suite available is not possible.