Feature: Add PublicList class

[glensc]

Add PublicList for:

• Refactor: Get rid of LazyUserList (port functionality to pytrakt) Taxel/PlexTraktSync#1826

movie_list = PublicList.load(trakt_id)
print(movie_list.description)

for m in movie_list:
  print(f"{m.rank}. {m.title}: {m.listed_at} {m.trakt}")

Actual usage example:

• Refactor to use PublicList class Taxel/PlexTraktSync#1843

Tests in a separate PR:

• Add PublicList tests #44

[glensc]

The module name where it's placed is perhaps odd:

from trakt.users import PublicList

[glensc]

@simonc56 any comments?

[simonc56]

I didn't test.
Maybe some tests for PublicList could be helpful.

[glensc]

@simonc56 so, no comments on code and naming?

• Feature: Add PublicList class #43 (comment)

[glensc]

Tests in a separate PR:

• Add PublicList tests #44