Add the configuration parameters to give users the option to turn on/off...

... auto-fix feature.

This pull request will add 3 additional azkaban configs:
project.validators.fix.prompt controls whether to show the auto-fix related UI
project.validators.fix.lable controls the content of the auto-fix label
project.validators.fix.link sets the link which contains the detailed information about the auto-fix feature.
I know the variable name `prop` is used elsewhere in Azkaban, but `props` makes more sense to me, since the object can hold multiple properties.