Deprecate the JS part of commons validator

The JS parts of commons-validator haven't been updated in a while and don't necessarily follow common security best practices (almost every function uses `eval`). At the same time there are quite a few issues that are several years old and haven't been worked upon [1].

For this reason I propose to deprecate (and later remove) the JS component of commons-validator using JavaDoc / JSDoc mechanisms and with a warning on the browser's console. All deprecation messages refer to an alternative that is commonly used and actively maintained to give the users some guidance.

[1] https://issues.apache.org/jira/browse/VALIDATOR-322?jql=project%20%3D%20VALIDATOR%20AND%20component%20%3D%20JavaScript%20AND%20status%20%3D%20Open%20ORDER%20BY%20priority%20DESC