Add rules documentation (level, category and description)

[ljmf00]

Code static analyzers should have a level, category and a description associated to each rule to let wrappers know the severity of the error, more about it and categorize to be more easy to search for specific errors (code style, error prone, security issues...)

I'm open to contribute and implement this, but before making a pull request, should discuss about the type of documentation that is going to be used. I suggest to follow this documentation. A json or xml and a specification for that file should be enough for wrappers to know how the tool work.