Split contextual footer menu migration

Problem/Motivation

When we upgraded the footer menus as part of the parent ticket, we added 3 menu items to the gcweb migration for the contextual footer menu. This is a nice feature that can be used to quickly migrate some test links to show a client. The issue we are running into now is that we use the gcweb migration to bring in all Canada.ca footer menu items for a given environment. In this case, we do not want test links in the contextual footer menu.

I propose we split out these 3 test menu items into it's own migration. This will allow us to use the Canada.ca footer link migration separately from the contextual menu items. This will allow us to support two main use cases; migrate links for demo, migrate links for production.

Steps to reproduce

$ drush migrate:import gcweb_menu_link

See the test contextual footer menu items.

Proposed resolution

Split the contextual menu items into their own migration, to allow them to be migrated separately. Also remove the dependency on wxt_node_page from the menu links so test content is not created in a production scenario.

Remaining tasks

N/A

User interface changes

A new migration is available, with ID gcweb_menu_link_contextual and gcweb_menu_link_contextual_translation.

API changes

N/A

Data model changes

N/A