Giftcard types doesn't show up in commerce configuration screen

Problem/Motivation

When you visit /admin/commerce/config there is no entry for gift card types. It appears in the dropdown menu if you have admin toolbar installed but otherwise site builders have no way to find the types page.

Steps to reproduce

Install commerce_giftcard on a commerce site
Visit the commerce configuration page /admin/commerce/config

Proposed resolution

All menu entries in that configuration screen have a category menu entry with the actual configuration pages listing that as the parent instead of commerce.configuration. We probably have to create a parent category for gift card configuration for it to show up there.

commerce_product.configuration:
  title: 'Products'
  route_name: 'commerce_product.configuration'
  parent: 'commerce.configuration'
  weight: -15

entity.commerce_product_type.collection:
  title: 'Product types'
  route_name: 'entity.commerce_product_type.collection'
  parent: 'commerce_product.configuration'
  description: 'Manage fields, form and display settings for your products.'

entity.commerce_product_variation_type.collection:
  title: 'Product variation types'
  route_name: 'entity.commerce_product_variation_type.collection'
  parent: 'commerce_product.configuration'
  description: 'Manage fields, form and display settings for your product variations.'

Remaining tasks

User interface changes

API changes

Data model changes