Add serde support for NodeRecord primitive type (#617)

* Add serde support to NodeRecord

* Move NodeRecord to primitives

along with NodeKey and Octets

* Reexport NodeRecord from discv4

* Move NodeKey and kad_key back to discv4::node

Also, move NodeRecord::key functionality to a helper function: discv4::node::record_key.
This avoids the discv5 dependency in the primitives crate.

* Fix NodeRecord (de)serializing

The default derive macros work with a dictionary like display.
Changed that to serde_with macros, that use Display and FromStr traits.

* Add some tests for NodeRecord (de)serializing

* Hide NodeKey struct

* Move Octets after NodeRecord

* Replace record_key with From trait

* Fix clippy error

unnecessary into()

crates/net/discv4/Cargo.toml

@@ -31,13 +31,12 @@ tokio-stream = "0.1"
 
 # misc
 bytes = "1.2"
-generic-array = "0.14"
 tracing = "0.1"
 thiserror = "1.0"
-url = "2.3"
 hex = "0.4"
 public-ip = "0.2"
 rand = { version = "0.8", optional = true }
+generic-array = "0.14"
 
 [dev-dependencies]
 rand = "0.8"
@@ -45,4 +44,4 @@ tokio = { version = "1", features = ["full"] }
 reth-tracing = { path = "../../tracing" }
 
 [features]
-mock = ["rand"]
+mock = ["rand"]