Moves HTTP/3 outside the experimental section

docs/content/migration/v2-to-v3.md

docs/content/reference/static-configuration/cli-ref.md

docs/content/reference/static-configuration/env-ref.md

docs/content/reference/static-configuration/file.toml

docs/content/reference/static-configuration/file.yaml

docs/content/routing/entrypoints.md

pkg/config/static/experimental.go

pkg/config/static/static_config.go