WebUI ftest framework features location

Currently the features location is hardcoded which means that we only have two options right now to use the framework on projects:

1. Replicate the hardcoded folder structure () on project's repo;
2. Duplicate WDIO configurations and also specs-processor;

The parameter already exists (see here) but it is not being used on specs-processor.
It would be interesting to make use of it in order to provide more configurability for the projects using the framework.