feat(metadata): improve CreateProvider

[vincentchalamon]

Q	A
Branch?	main
Tickets	N/A
License	MIT
Doc PR	N/A (@internal and @experimental)

Improve CreateProvider with parent_uri_template context option, and remove the new Get. If no parent_uri_template option is provided, get the first operation found as it's already done in core.

• Set CreateProvider as @internal.
• Inject CallableProvider instead of Doctrine ItemProvider in CreateProvider
• Retrieve parent operation using parent_uri_template, or first operation available by default