The export host option allows users to export their existing host
information for import into a third party system. The output is
'pivoted', so that the key is the host/container name, and the values
are the group memberships and hostvar information. Some top level
networking information, such as load balancer IP addresses, as well as
provider networks, are also provided.
Test scaffolding was added to ensure the export does what is intended.
The tox inventory environment was modified to do coverage testing of
both the dynamic_inventory.py and manage_inventory.py files. The
coverage data is erased between runs, since combined output lead to
incorrect results for dynamic_inventory.py.
Change-Id: I2caa5a0c070b12a74ac26334c63ac8d0de704042