feat(Channel): add support for sorting the playlist tab

[LuanRT]

Description

Adds support for sorting the playlist tab, see #290 for more details.

Usage

import { Innertube, UniversalCache } from 'youtubei.js';

(async () => {
  const yt = await Innertube.create({ cache: new UniversalCache(), generate_session_locally: true });

  const channel = await yt.getChannel('UCez-2shYlHQY3LfILBuDYqQ');

  let playlists_tab = await channel.getPlaylists();

  /**
   * Channels such as UCez-2shYlHQY3LfILBuDYqQ have their playlists organized into various categories. 
   * In this case, sorting is only possible after a category is selected.
   */
  if (!playlists_tab.memo.has('SortFilterSubMenu')) {
    console.info('Content type filters:', playlists_tab.content_type_filters);
    playlists_tab = await playlists_tab.applyContentTypeFilter('Created playlists');
  }

  console.info('Sort filters:', playlists_tab.sort_filters);

  const sorted_playlist_tab = await playlists_tab.applySort('Last video added');

  console.log(sorted_playlist_tab);
})();

Closes #290.

Type of change

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

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have checked my code and corrected any misspellings