Fixes bug 1096552 create dataservice

This is a portion of work done in this branch: https://github.com/twobraids/socorro/compare/simple-middle

The idea was to make this more easily reviewable than the earlier, more comprehensive patch.

This patch implements: 

* DataserviceApp - a refactoring of MiddlewareApp to be simpler and to operate more like crontabber -- using our `socoro/external` class interfaces for accessing data, rather than a custom interface.
* Bugs - an implementation of a dataservice that demonstrates the future of how we provide data through Dataservices API in the future
* tests - I didn't remove all of the tests that were implemented for the future dataservice implementations. I just marked them as skipped for now.

There's some additional work that was done in the `socorro/external/postgresql` classes that I may end up taking out as I do another review. 

This is all really @twobraids' work, with me renaming the refactored code to 'dataservice' and some cleanup work to make it possible to run both the middleware_app.py and dataservice_app.py at the same time. 

Once we've settled on this code, we can add the rest of the services in another PR and the finally work on making these classes accessible in the Django app.
I'm really not sure this file is worth keeping. I know it's a copy of `test_middleware_app.py` with a bunch of `raise SkipTest` added. 

Some day soon we'll stop using `dataservice_app.py` and just have django talking directly to s3,es,pg etc. That's the stuff we want to maintain and we only want tests for stuff we care to maintain. 

Secondly, I'm really having second thoughts about its use at all. Even for `test_middleware_app.py`. What it actually does is tests the implementations but it does so going through the middleware/dataaservice app. There are better tests elsewhere for things like the functionality in `socorro/external/postgresql/crashes.py` for example. No need to test that again but through a different interface. 

Even if it leaves us in a time-based hole of less test coverage I think we ought to drop this. Otherwise we become slaves to the tests and not the other way around. 

What do you think?