Better description in README file

[michelvocks]

I heard from a lot of people that the description (README file) is not very clear. Especially the term "pipeline" led to confusion. We should improve this soon to make clear what Gaia is and maybe how is it comparable to other projects (competitors).

[issmirnov]

A good addition would be a clear explanation of what problems this is solving. I read the README and the Tutorials and still don't understand what need this fulfills. Is this a deployment tool? Orchestration? Fancy build tool or glorified scripting language? Etc.

[michelvocks]

@issmirnov please see #50. I added a Q&A section which describes this a bit and did some minor improvements. It's hard to say that Gaia is only for deployment or Orchestration or whatever. Gaia can be anything. I think there are several use-cases out there which we event don't imagine yet 😄