Update the documentation with platforms requirements (#37)

This is for issue#37, I updated the requirements we need to have on client/slave nodes in order to be able to run tps testruns.
@whimboo can you review this?
Note that the new lines here will not carry across to the rendered document. If you intended these to be on a separate line then you will need to have two new lines. Also, a minor nit but please end your sentence with a period.