Initial implementation of service_catalog panel.

Implemented getting list of services, actions 'Toggle Active',
'Download Service', 'Delete Service'.

Action 'Upload Service' is implemented, but currently does not
work properly.

Action 'Compose Service'/'Modify Service' is under construction as
well as the corresponding form. 'Metadata Objects' table (which can be
accessed from 'Compose Service' form) is yet to come.

Change-Id: I37e411fba01819a5d4a61978a283bcb6a45f2e55