Remove Create Item Modal from Dashboard and List views

[raveling]

The Create Item Modal should be removed when creating new items from the dashboard and list views in favour of creating directly within the item view.

The current approach to making new items from all create actions imposes a 2-step approach on Admin UI users.

1. Undertake a complete or partial edit in the modal
2. After the create button has been pressed in the modal, continue editing/updating in the default item view

This modal-enabled journey is useful when a user may have unsaved changes in a previous context (i.e. creating a new related category while editing post). But in situations where preservation of the original context is not important, the modal is a productivity impediment.

Related discussions

• Grab-bag of Admin UI Customisation Requests #5309 (comment)
• Enhance create item drawer, and use more screen space #5455
• https://keystonejs.slack.com/archives/C01STDMEW3S/p1652780436225789?thread_ts=1652780167.599079&cid=C01STDMEW3S