Added cache_builders granularity to letterboxd defaults

[Kevin2kkelly]

Description

Added the ability to set the value for cache_builders at the individual collection level for Letterboxd defaults. A couple lists are 1k+ items, so this allows cache_builders to be set higher for just those collections, or any combination the user chooses.

The below will create all 16 default Letterboxd collections and set cache_builders to 7 for all collections except the four collections explicitly defined using cache_builders_<<key>>.

libraries:
  Test-Movies:
    collection_files:
      - default: letterboxd
        template_variables:
          use_imdb_top_250: true
          use_oscars: true
          use_cannes: true
          cache_builders: 7
          cache_builders_boxofficemojo_100: 2
          cache_builders_afi_100: 3
          cache_builders_1001_movies: 30
          cache_builders_edgarwright: 30

Type of Change

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• New feature (non-breaking change which adds functionality)

Checklist

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• Updated Documentation to reflect changes