Upgrade to tokio 0.3 (#1839)

## Description

This PR updates Lighthouse to tokio 0.3. It includes a number of dependency updates and some structural changes as to how we create and spawn tasks.

This also brings with it a number of various improvements:

- Discv5 update
- Libp2p update
- Fix for recompilation issues
- Improved UPnP port mapping handling
- Futures dependency update
- Log downgrade to traces for rejecting peers when we've reached our max



Co-authored-by: blacktemplar <blacktemplar@a1.net>

common/warp_utils/Cargo.toml

@@ -7,14 +7,14 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-warp = { git = "https://github.com/paulhauner/warp", branch = "cors-wildcard" }
+warp = { git = "https://github.com/sigp/warp ", branch = "lighthouse" }
 eth2 = { path = "../eth2" }
 types = { path = "../../consensus/types" }
 beacon_chain = { path = "../../beacon_node/beacon_chain" }
 state_processing = { path = "../../consensus/state_processing" }
 safe_arith = { path = "../../consensus/safe_arith" }
 serde = { version = "1.0.116", features = ["derive"] }
-tokio = { version = "0.2.22", features = ["sync"] }
+tokio = { version = "0.3.2", features = ["sync"] }
 headers = "0.3.2"
 lighthouse_metrics = { path = "../lighthouse_metrics" }
 lazy_static = "1.4.0"