Constrain the data provided by ECP Validator

The previous response gave to much information to the ECP Client
potentially allowing it to be utilised for purposes which aren't about
testing an ECP client works correctly.
Updated wording to clarify the project's intention

Some of the existing wording was ambiguous, and code example outdated.
Merge pull request #1 from ausaccessfed/feature/reduce-information-ecpvalidator-provides

Reduce information ecpvalidator provides