installation: Elasticsearch 2 in Docker

• FIX Pins Elasticsearch PyPI dependencies to use version 2 and configures Docker to use Elasticsearch version 2 rather than version 5 for which some of the Invenio packages are not ready yet. This harmonises the use of Elasticsearch version 2 for both Docker and Vagrant based installation procedures. (closes #3714)

• Increments versions of several Invenio packages.

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>