Add SKU list create and update pages

[pfferrari]

What I did

Added the form related pages of the app to manage SKU list creation and update.

This task was completed by:

• creating a shared form component along with a valid zod schema able to manage both manual and automatic SKUs management ways used in sku_lists resources
• defining dedicated hooks based on the same approach to manage create and update procedure

More in detail create and update actions share the same UI but need a slightly different treatment:

• When a sku_lists resource is saved for creation at first it is created by saving its own data (like name, manual and sku_code_regex (if manual is set to false)). Then, once the creation is ok, it is necessary to create related
  sku_list_items only if manual prop is set to true.
• When a sku_lists resource is saved for update its related sku_list_items, if present, need a particular treatment in order to remove the ones that are anymore need, update the ones that are changed and create the ones that were not existing.
  This two procedures were managed in useCreateSkuList and useUpdateSkuList hooks for a better readability and at the same time to keep separated the two tasks.

Improvements

• Filter the Pick a SKU page to remove items the are already selected [waiting for new app-elements version to have the fix]
• Add the proper link to the hint of Automatic regex field
• Add documentation to all methods defined
• Fix a bug related to the input spinner + - quantity selector visible when the items are added and then deleted

Checklist

• Make sure your changes are tested (stories and/or unit, integration, or end-to-end tests).
• Make sure to add/update documentation regarding your changes.
• You are NOT deprecating/removing a feature.