proxy: merge connect compute (#4713)

## Problem

Half of #4699.

TCP/WS have one implementation of `connect_to_compute`, HTTP has another
implementation of `connect_to_compute`.

Having both is annoying to deal with.

## Summary of changes

Creates a set of traits `ConnectMechanism` and `ShouldError` that allows
the `connect_to_compute` to be generic over raw TCP stream or
tokio_postgres based connections.

I'm not super happy with this. I think it would be nice to
remove tokio_postgres entirely but that will need a lot more thought to
be put into it.

I have also slightly refactored the caching to use fewer references.
Instead using ownership to ensure the state of retrying is encoded in
the type system.

proxy/src/console/provider.rs

@@ -186,14 +186,14 @@ pub trait Api {
     async fn get_auth_info(
         &self,
         extra: &ConsoleReqExtra<'_>,
-        creds: &ClientCredentials<'_>,
+        creds: &ClientCredentials,
     ) -> Result<Option<AuthInfo>, errors::GetAuthInfoError>;
 
     /// Wake up the compute node and return the corresponding connection info.
     async fn wake_compute(
         &self,
         extra: &ConsoleReqExtra<'_>,
-        creds: &ClientCredentials<'_>,
+        creds: &ClientCredentials,
     ) -> Result<CachedNodeInfo, errors::WakeComputeError>;
 }
 

proxy/src/console/provider/mock.rs

@@ -106,7 +106,7 @@ impl super::Api for Api {
     async fn get_auth_info(
         &self,
         _extra: &ConsoleReqExtra<'_>,
-        creds: &ClientCredentials<'_>,
+        creds: &ClientCredentials,
     ) -> Result<Option<AuthInfo>, GetAuthInfoError> {
         self.do_get_auth_info(creds).await
     }
@@ -115,7 +115,7 @@ impl super::Api for Api {
     async fn wake_compute(
         &self,
         _extra: &ConsoleReqExtra<'_>,
-        _creds: &ClientCredentials<'_>,
+        _creds: &ClientCredentials,
     ) -> Result<CachedNodeInfo, WakeComputeError> {
         self.do_wake_compute()
             .map_ok(CachedNodeInfo::new_uncached)

proxy/src/console/provider/neon.rs

@@ -123,7 +123,7 @@ impl super::Api for Api {
     async fn get_auth_info(
         &self,
         extra: &ConsoleReqExtra<'_>,
-        creds: &ClientCredentials<'_>,
+        creds: &ClientCredentials,
     ) -> Result<Option<AuthInfo>, GetAuthInfoError> {
         self.do_get_auth_info(extra, creds).await
     }
@@ -132,7 +132,7 @@ impl super::Api for Api {
     async fn wake_compute(
         &self,
         extra: &ConsoleReqExtra<'_>,
-        creds: &ClientCredentials<'_>,
+        creds: &ClientCredentials,
     ) -> Result<CachedNodeInfo, WakeComputeError> {
         let key = creds.project().expect("impossible");