RuntimeApis not exposed in the parachain template

[th7nder]

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Description of bug

Hey all,

The parachain template is by configured by default in a way, that does not expose the Runtime API calls information.
That's because impl_runtime_apis! macro is used in a separate module (apis) and it breaks the trait visibility.

I found the issue originally when integrating with subxt, more details on the investigation are here: paritytech/subxt#1873.

Steps to reproduce

#3817 -> introduced a refactoring of the parachain template.
It moves the impl_runtime_apis decl into another module called apis.
Effectivly, trait InternalImplRuntimeApis ends up being under crate::apis::InternalImplRuntimeApis, not in the crate::InternalImplRuntimeApis.

When construct_runtime macro is expanded and uses (&rt).runtime_metadata, it's expanded under crate::* and has no visibility into crate::apis::InternalImplRuntimeApis, because:
a) trait is private
b) construct macro is not importing api::*

So in the end, the 'default, backward compatible' implementation is used.