Restructuring and renaming of MQNaaS

Complete restructuring and renaming of MQNaaS projects, Maven submodules, OSGi bundles and Karaf features.

New and noteworthy:
* MQNaaS root project is a Maven parent project without source code.

 It is formed by these Maven submodules:
 * `core.api`

    An OSGi bundle containing all the interfaces and annotations.

 * `core`

    An OSGi bundle containing implementation.

 * `clientprovider`

    An OSGi bundle containing classes to help implementing client to be used in MQNaaS.

 It produces a Karaf feature called `mqnaas` with all these bundles and its dependencies.

* `examples` is a subfolder containing a parent Maven project without source code. It is composed by a few Maven submodules, being an OSGi bundle each one. It generates a Karaf feature called `mqnaas-examples` containing all these example bundles and its dependencies.

Moreover bugfixes are solved.