Manual registration of validators

[mokkabonna]

The big set of validators can result in many unused validators being bundled in a build.

Consider an approach that the user need to manually pick what validation keywords to support. And make it easy to choose all. Many users might not need all the advanced validators. Also allow the option to throw or log when a validation keyword is present in the schema but that validator isn't loaded.

This would also align well with the intensioon to support custom format validators.