Migration: Schema Records

[leoeuclids]

This PR migrates ember-data models to schema records.

Reason

As a part of the effort to update documentation and guides to use schema records, as outlined in warp-drive-data/warp-drive#9695

What it does

• Deletes the rental model
• Adds the rental schema definition
• Adds a store service implementation that extends from @ember-data/store
• Adds the cache handler to the request manager service

[netlify]

👷 Deploy request for ember-super-rentals pending review.

Visit the deploys page to approve it

Name	Link
🔨 Latest commit	515feee

[leoeuclids]

The store implementation also fixes the deprecation addressed in #170