Add manage app config (for MDM) for videos and streams

This adds support for Managed App Configuration so that a list of video files/streams can be delivered via an MDM solution, such as Jamf. If the server-list key is sent, this will add a Managed tab that can reference video streams for the tvOS app.

Here's an example app configuration that could be used:

<dict>
		<key>server-list</key>
		<array>
                        <dict>
                               <key>name</key>
                               <string>Example 1</string>
                               <key>url</key>
                               <string>https://sample-videos.com/video123/mp4/720/big_buck_bunny_720p_1mb.mp4</string>
                        </dict>
                        <dict>
                               <key>name</key>
                               <string>Example 2</string>
                               <key>url</key>
                               <string>https://sample-videos.com/video123/mp4/240/big_buck_bunny_240p_30mb.mp4</string>
                        </dict>
		</array>
</dict>

Our basic use case is to add non-public facing IP cams that we can then push to many different Apple TVs in our organization.

If this request is accepted, I will add a section to the tvOS section of the VLC documentation wiki.