Add support for a well defined project structure

[oconnormi]

The direction we would like to move in is for a well defined project structure where specific folders under a project root have real meaning within testify.

For example:

- project
|  +  prep
    |  - fooStep.xml
    |  - barStep.yml
|  +  properties
    |  - stuff.properties
    |  - moreStuff.yml
|  +  data
    |  - bigPayload.xml
    |  - someFile.jpg
|  +  tests
    |  - testSomeFile.xml
    |  - testPayload.yml
|  -  .testify (Testify settings and project root marker)
|  -  README.md

[oconnormi]

Initial steps to support this have been to define the project structure within a .testify.yml file in th root of the project, this allows for reconfiguring how a project is structured if it is desired to do so.