Add My WordPress travel apps and app alternatives recipe

[akirk]

Summary

• add Travel App and Flight Log app blueprints to My WordPress
• add a travel planning recipe that uses Travel App and Flight Log
• add a familiar app alternatives recipe using the new recipe alternatives table
• document the new alternatives recipe field

Depends on akirk/my-apps#133 for schema and renderer support.

Testing

• npm run validate:my-wordpress-json passed when pointed at the updated local My Apps schema
• npm run validate:pr-blueprints passed for the touched blueprint directories

Note: the default npm run validate:my-wordpress-json currently fails against the upstream My Apps schema until akirk/my-apps#133 lands.

[github-actions]

Test using WordPress Playground

The changes in this pull request can be previewed and tested using a WordPress Playground instance.

WordPress Playground is an experimental project that creates a full WordPress instance entirely within the browser.

Some things to be aware of

• All changes will be lost when closing a tab with a Playground instance.
• All changes will be lost when refreshing the page.
• A fresh instance is created each time one of the links below is clicked.

For more details about these limitations and more, check out the Limitations page in the WordPress Playground documentation.

Blueprint previews

• Open flight-log in WordPress Playground
• Open travel-app in WordPress Playground