[1.0.0-alpha1] Rename DisplayBuilderPreset

Let' use sentence case ("Pattern preset") instead of title case ("Pattern preset") for entity label because it is what Core do for other config entities.

This is also the opportunity of rewording some parts:

• "A Pattern preset is used in the library of preset in a display builder." > "A Pattern preset is a reusable arrangement of components."
• "List of display builder presets to extend site functionality." > "Available pattern presets."
• "List of display builder presets to extend site functionality." > "Add a pattern preset"
• "Pattern preset configuration" > "Pattern presets"

Automatically closed - issue fixed for 2 weeks with no activity.