Denis Matousek

Add check of uniqueness of control plane names

7

[Control plane names](https://p4.org/p4-spec/docs/P4-16-v1.2.2.html#sec-control-plane-api-annotations) are not checked for uniqueness. It may lead to various issues in subsequent passes when uniqueness is assumed.

According to the [spec](https://staging.p4.org/p4-spec/docs/P4-16-v1.2.4.html#sec-type-nesting), tuple fields should adhere to the same rules as struct fields.