decouple eth2 from store and lighthouse_network (#6680)

- #6452 (partially)


  Remove dependencies on `store` and `lighthouse_network`  from `eth2`. This was achieved as follows:

- depend on `enr` and `multiaddr` directly instead of using `lighthouse_network`'s reexports.
- make `lighthouse_network` responsible for converting between API and internal types.
- in two cases, remove complex internal types and use the generic `serde_json::Value` instead - this is not ideal, but should be fine for now, as this affects two internal non-spec endpoints which are meant for debugging, unstable, and subject to change without notice anyway. Inspired by #6679. The alternative is to move all relevant types to `eth2` or `types` instead - what do you think?

common/eth2/Cargo.toml

@@ -3,19 +3,20 @@ name = "eth2"
 version = "0.1.0"
 authors = ["Paul Hauner <paul@paulhauner.com>"]
 edition = { workspace = true }
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
 derivative = { workspace = true }
 either = { workspace = true }
+enr = { version = "0.13.0", features = ["ed25519"] }
 eth2_keystore = { workspace = true }
 ethereum_serde_utils = { workspace = true }
 ethereum_ssz = { workspace = true }
 ethereum_ssz_derive = { workspace = true }
 futures = { workspace = true }
 futures-util = "0.3.8"
-lighthouse_network = { workspace = true }
+libp2p-identity = { version = "0.2", features = ["peerid"] }
 mediatype = "0.19.13"
+multiaddr = "0.18.2"
 pretty_reqwest_error = { workspace = true }
 proto_array = { workspace = true }
 reqwest = { workspace = true }
@@ -25,7 +26,6 @@ serde = { workspace = true }
 serde_json = { workspace = true }
 slashing_protection = { workspace = true }
 ssz_types = { workspace = true }
-store = { workspace = true }
 types = { workspace = true }
 zeroize = { workspace = true }