Added APIs for managing permissions, playlists, channels, and videos

Added

• New Permissions APIs:
  • GET /v2/video_management/channels/{channelId}/permissions
  • POST /v2/video_management/channels/{channelId}/permissions
  • PATCH /v2/video_management/channels/{channelId}/permissions
  • DELETE /v2/video_management/channels/{channelId}/permissions
• New Playlists APIs:
  • DELETE /v2/video_management/channels/{channelId}/playlists
  • GET /v2/video_management/channels/{channelId}/playlists
  • PATCH /v2/video_management/playlists/{playlistId}
  • GET /v2/video_management/playlists
  • POST /v2/video_management/channels/{channelId}/playlists
  • DELETE /v2/video_management/playlists/{playlistId}
  • POST /v2/video_management/playlists
• New Channels APIs:
  • GET /v2/video_management/channels
  • PATCH /v2/video_management/channels/{channelId}
  • POST /v2/video_management/channels
  • PATCH /v2/video_management/channels/{channelId}/actions
  • GET /v2/video_management/channels/{channelId}
  • DELETE /v2/video_management/channels/{channelId}
• New Videos APIs:
  • GET /v2/video_management/videos
  • GET /v2/video_management/playlists/{playlistId}/videos
  • DELETE /v2/video_management/channels/{channelId}/videos
  • POST /v2/video_management/playlists/{playlistId}/videos
  • DELETE /v2/video_management/playlists/{playlistId}/videos
  • POST /v2/video_management/channels/{channelId}/videos
  • GET /v2/video_management/channels/{channelId}/videos