Add trakt official lists support

[simonc56]

With this PR, the script handles trakt lists with their id instead of there creator name.
This allows to use user lists and official lists with the same function.
Official lists are not identical to user lists because they are not created bu users and cannot be called with /users/(user)/lists/(list)

Ideally, the pytrakt module would add official lists support.

Example of official lists :
https://trakt.tv/lists/official/scream-collection
https://trakt.tv/lists/official/diary-of-a-wimpy-kid-animated-collection
https://trakt.tv/lists/official/lee-rock-collection
https://trakt.tv/lists/official/alien-40th-anniversary-short-films-da668a6d-5378-4e32-a8a9-af3366c27805

[glensc]

install from pull request instructions:

• https://github.com/Taxel/PlexTraktSync#install-code-from-pull-request

[glensc]

I asked @bulletproof2k to test this pr:

• Trakt official lists raise : 'TraktList' object has no attribute 'trakt_items' #1161 (comment)
• Trakt official lists raise : 'TraktList' object has no attribute 'trakt_items' #1161 (comment)
• Trakt official lists raise : 'TraktList' object has no attribute 'trakt_items' #1161 (comment)