Allow programmatic module sharding configuration

Allow programmatic module sharding configuration

Adds the option to create Configuration without the need for
module-shards.conf file. Current version only accepts a path
to the module-shards.conf. The file is later loaded and
deserialized into a Config object. This patch provides the
option to pass the Config object directly.

Change-Id: Ibeb666bd5f01d7ae972d26453046c959749a0656
Signed-off-by: Tibor Král <tibor.kral@pantheon.tech>
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>