Add class for all strings constant parameters

[pedsf1968]

Branch : develop-6.0.x

It's better to avoid mistakes to use final Class to declare all Strings constants like attributes, errors or paths.

We can create a class in package org.broadleafcommerce.common for all modules for BroadLeafCommerce Attributes :

Branch : develop-6.0.x
Feature : centralise-string-const
Package : org.broadleafcommerce.common
Class name : BLCA
Attributes starting with ATTRIBUTE_
Errors starting with ERROR_
Paths starting with PATH_

BLCA in package org.broadleafcommerce.common

and use like this in org.broadleafcommerce.profile.web.controller.validator.CustomerPhoneValidator Class

CustomerPhoneValidator in package org.broadleafcommerce.profile.web.controller.validator

I can implementing this basic feature for my first contribution to your project.
I'm waiting for your opinion

I thing i'ts better to separate Attributes, Errors and Paths in separates classes like:

• CommonAttribute
• CommonPath
• CommonError

[pedsf1968]

last attribute of rejectValue method isn't @nullable use method with only 2 args.

in Erros.class
void rejectValue(@nullable String var1, String var2);
void rejectValue(@nullable String var1, String var2, String var3);
void rejectValue(@nullable String var1, String var2, @nullable Object[] var3, @nullable String var4);

[pedsf1968]

create feature centralise-string-const