Naming has been changed to to validate.

Having been able to use Maat in multiple projects, and teams.
It became clear that serialization part was not used often.
Thus new version is created named validate

The validate_args decorator has been renamed to protected.
maat.protected

Some changes that are breaking
the keywords:

• validator has been changed to type
• default_value has been changed to default

The rest of the changes are some housekeeping.