View encryption metadata for encrypted volumes

Summary
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This proposed feature is to add the capability to see the encryption metadata for volumes that are encrypted, including cipher, key size, provider, name, and control location.

Motivation
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As of Horizon patch [1], it is now possible to see whether a volume is encrypted or not in Horizon. However, it is not possible to see the encryption metadata for the volume, only that it is encrypted or not encrypted.

Description
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The user will be able to click on the "Yes" in the Encrypted column, and be taken to a page where the encryption metadata is visible.

UX
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Instead of only seeing whether a volume is encrypted or not encrypted, the user will now be able to see the encryption metadata associated with the volume.
Wireframes, Mocks, Videos and UI Markup: N/A

Testing
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Create a Volume Type as an admin. Create Encryption for that volume type, defining the cipher, key size, provider, and control location. Create a volume with that encrypted volume type. Click on the value in the "Encrypted" column of the volume. Confirm that the encryption metadata defined as a part of the volume type is now displayed for that volume. Create a volume with a volume type that is not encrypted, and confirm that no encryption metadata is displayed when the value of the Encrypted column is clicked.

Outside Dependencies
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Retrieving the encryption metadata about a specific volume is supported by cinder as a part of an API extension [2]. This extension is also supported in python-cinderclient [3].

Requirements Update Required
========================
N/A

Doc Impact
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N/A

[1] https://review.openstack.org/#/c/71125/
[2] https://github.com/openstack/cinder/blob/master/cinder/api/contrib/volume_encryption_metadata.py
[3] https://github.com/openstack/python-cinderclient/blob/master/cinderclient/v2/volumes.py#L430