fix: Remove circular dependencies across workspace (#3023)

Circular dependencies are problematic in several ways:

- They result in cognitive overhead for developers, in trying to figure out what depends on what.
- They present `cargo` with limits in what order the crates can be compiled in.
- They invalidate build caches unnecessarily thus forcing `cargo` to rebuild certain crates.
- They cause problems with tooling such as `release-please`.

To actually break the circular dependencies, this patch inlines the uses of `development_transport` in the examples and tests for all sub-crates. This is only meant to be a short-term fix until https://github.com/libp2p/rust-libp2p/issues/3111 and https://github.com/libp2p/rust-libp2p/pull/2888 are fixed.

To ensure we don't accidentally reintroduce this dependency, we add a basic CI that queries `cargo metadata` using `jq`.

Resolves https://github.com/libp2p/rust-libp2p/issues/3053.
Fixes https://github.com/libp2p/rust-libp2p/issues/3223.
Related: https://github.com/libp2p/rust-libp2p/pull/2918#discussion_r976514245
Related: https://github.com/googleapis/release-please/issues/1662

protocols/mdns/src/behaviour/timer.rs

@@ -20,18 +20,17 @@
 
 use std::{
     marker::Unpin,
-    pin::Pin,
-    task::{Context, Poll},
     time::{Duration, Instant},
 };
 
-/// Simple wrapper for the differents type of timers
+/// Simple wrapper for the different type of timers
 #[derive(Debug)]
+#[cfg(any(feature = "async-io", feature = "tokio"))]
 pub struct Timer<T> {
     inner: T,
 }
 
-/// Builder interface to homogenize the differents implementations
+/// Builder interface to homogenize the different implementations
 pub trait Builder: Send + Unpin + 'static {
     /// Creates a timer that emits an event once at the given time instant.
     fn at(instant: Instant) -> Self;
@@ -48,6 +47,10 @@ pub mod asio {
     use super::*;
     use async_io::Timer as AsioTimer;
     use futures::Stream;
+    use std::{
+        pin::Pin,
+        task::{Context, Poll},
+    };
 
     /// Async Timer
     pub type AsyncTimer = Timer<AsioTimer>;
@@ -86,6 +89,10 @@ pub mod tokio {
     use super::*;
     use ::tokio::time::{self, Instant as TokioInstant, Interval, MissedTickBehavior};
     use futures::Stream;
+    use std::{
+        pin::Pin,
+        task::{Context, Poll},
+    };
 
     /// Tokio wrapper
     pub type TokioTimer = Timer<Interval>;