MODE-1667 Updated the API for RepositoryFactory and general repository container functionality

There are a couple of significant changes:
- a new service interface `RepositoriesContainer` was added to the API that exposes functionality for retrieving repositories by name, retrieving all the repository names and shutting repositories down
- the implementing class (from the jcr package) `JcrRepositoriesContainers` contains all the functionality for resolving & initializing repositories (either from the filesystem or JNDI)
- `RepositoryFactory` does not implement the `Repositories` interface anymore and does not act as a container of repositories. It still has the `shutdown` methods, but they have been deprecated
- `JcrRepositoryFactory` remains the only service implementation and uses internally the `JcrRepositoriesContainer` class.
- web clients (via the `RepositoryManager` class) use & delegate to the first `RepositoriesContainer` implementation they find in the classpath.
- the `Repositories` interface was left unchanged, with one implementing class `ModeshapeEngine`. It is used by repository clients (e.g. JDBC clients) to access the engine.