Validator Base creation

[RaiBnod]

Ticket: #43

Basic idea of the validation base is extracted from joi.

Our validation base should able to do validation of Java primitives, objects as well as the JSON. And also it should able to assign some default values.

[zero88]

• Introduce DataTypeValidation with abstract classType method, then all kinds such as StringValidation, DoubleValidation extends on this class.
• Test no need logger, use system.out. If you need logger, pls adapt to use TestHelper for setupClass. Remove TestBase, it doesn't existed anymore
• Each Test method must validate one case

[zero88]

Request changes

[RaiBnod]

@Zero-88 please proceed for reviewing...

[zero88]

@RaiBnod
Actually, after more reading your code, I feel it is too complex to understandable.
You made:

• Mixing validate plain java type and JSonObject, all in one. A boundary between them is very ambiguous.
• Use Java generic is not useful and effective.
• Why validate need Single.
• Naming classes is confusing

I suggest an another solution in package com.nubeiot.core.validator.proposal, it is just interface and some mock steps with comments.
I'd like to expect that you can review and re-think to design core API more intuitive

Thanks

[RaiBnod]

Refactoring the ValidationBases are done. @Zero-88, could you please review the changes.