Fix DBAL 4 compatibility

[derrabus]

DBAL 4's switch to enums made some changes necessary. Maybe it would be wise at this point to introduce our own enums for LockMode and ParameterType, to be more resilient to this kind of changes?

[morozov]

Maybe it would be wise at this point to introduce our own enums for LockMode and ParameterType, to be more resilient to this kind of changes?

Eventually, similar to the replacement of the DBAL's FetchMode with a set of fetch*() methods (doctrine/dbal#4019), I'd like to make the parameter type enum internal and replace it with the methods like bindInteger(), bindString(), etc in the userland.

On the one hand, it will improve the type safety of the code, on the other, there will be no longer the need to keep the ParameterType::STRING binding type as the default.