Add more functions for OpenVSwitch

[smarsching]

What does this PR do?

This PR makes changes to the openvswitch_bridge state and the openvswitch execution module it also introduces a new openvswitch_db state module.

Changes to salt.modules.openvswitch:

• The bridge_create function has two new (optional) parameters. By specifying these parameters, one can create a "fake bridge" that represents a certain VLAN on a regular bridge.
• The db_get function has been added. It provides a way to read a value directly from the OpenVSwitch database, thus giving access to nearly every aspect of the OpenVSwitch configuration.
• The db_set function has been added. It provides a way to write a value directly to the OpenVSwitch database, thus giving access to nearly every aspect of the OpenVSwitch configuration.

Changes to salt.states.openvswitch_bridge:

• The present function has two new (optional) parameters. By specifying these parameters, one can create a "fake bridge" that represents a certain VLAN on a regular bridge.

New module salt.states.openvswitch_db:

• Provides a managed function that helps one ensure that certain columns of a record in the OpenVSwitch database have certain values. For example, this can be used to set a fixed MAC address for an "internal" interface.

Tests written?

No

Commits signed with GPG?

No

[cachedout]

@jirikotlin can you help us review this?

[smarsching]

It looks like this never got carried from develop to master. Was this just overlooked or is there a reason for that?

[sagetherage]

@smarsching simply have not cleaned up -- thank you!!