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 suggest replacing lines 1427-1431 with:
```
if (autoFix.equals("on")) {
  prop.put(ValidatorConfigs.CUSTOM_AUTO_FIX_FLAG_PARAM, "true");
} else {
  prop.put(ValidatorConfigs.CUSTOM_AUTO_FIX_FLAG_PARAM, "false");
}
```