feat: Render Custom widget for standalone array fields

[alfonsoar]

Reasons for making this change

This PR should fix #1385

It allows developers to specify a array in the schema without having to specify an enum or uniqueItems.

Checklist

• I'm adding or updating code
  • I've added and/or updated tests
  • I've updated docs if needed
  • I've updated the changelog with a description of the PR
• I'm updating documentation
  • I've checked the rendering of the Markdown text I've added
• I'm adding a new feature
  • I've updated the playground with an example use of the feature

[alfonsoar]

There are a ton of package-lock.json changes. Not sure if that is expected but it's a bit risky. Should we just omit them?

[epicfaace]

Documentation we need to change:

• https://react-jsonschema-form.readthedocs.io/en/latest/advanced-customization/custom-templates/#arrayfieldtemplate - add a note at beginning that mentions you can use ui:widget for arrays as well
• https://react-jsonschema-form.readthedocs.io/en/latest/advanced-customization/custom-widgets-fields/#adding-your-own-custom-widgets - add "array" as a type that supports widgets
• https://react-jsonschema-form.readthedocs.io/en/latest/usage/arrays/#multiple-choice-list - put "MCL" under a new section called "custom widgets", also talk about how you can use a custom widget in general for an array

[epicfaace]

Revert package-lock.json changes, keep them locally if needed