Add ability to assign cisco network profile to multiple tenants

Summary
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Add the ability to assign a Cisco N1kv network profile to multiple tenants during network profile creation and updation.

Motivation
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Currently, a Cisco N1kv network profile can be associated with only one tenant. However, the N1kv neutron plugin is capable of assigning multiple tenants to a profile. This change would make the dashboard consistent with the neutron plugin.

Description
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The changes would be made in the Cisco Nexus 1000V router tab. The create network profile form and the edit network profile forms will have a multi-select drop-down instead of a single select drop-down list. The api call to neutron would be modified with additional parameters in the REST request for adding/removing lists of tenants.

UX
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NA

Wireframes, Mocks, Videos and UI Markup
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NA

Testing
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While creating a network profile from the Cisco Nexus 1000V router tab, select multiple tenants from the drop down. Edit this network profile and ensure the tenants selected have a check against them. Unselect some of the existing tenants, choose new ones and update. The table should show the updated tenant list.

Outside Dependencies
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Associating multiple tenants with a N1kv network profile is already supported by the Neutron plugin. The existing API call to neutron would be modified with parameters for adding/removing tenants added to the REST payload. The API calls (from python neutron-client) being used are api.neutron.profile_create() and api.neutron.profile_update().

Requirements Update Required
========================
NA

Doc Impact
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NA