Add SensitiveUrl to redact user secrets from endpoints (#2326)

## Issue Addressed

#2276 

## Proposed Changes

Add the `SensitiveUrl` struct which wraps `Url` and implements custom `Display` and `Debug` traits to redact user secrets from being logged in eth1 endpoints, beacon node endpoints and metrics.

## Additional Info

This also includes a small rewrite of the eth1 crate to make requests using `Url` instead of `&str`. 
Some error messages have also been changed to remove `Url` data.

beacon_node/http_api/Cargo.toml

@@ -35,3 +35,4 @@ store = { path = "../store" }
 environment = { path = "../../lighthouse/environment" }
 tree_hash = "0.1.1"
 discv5 = { git = "https://github.com/sigp/discv5 ", rev = "02d2c896c66f8dc2b848c3996fedcd98e1dfec69", features = ["libp2p"] }
+sensitive_url = { path = "../../common/sensitive_url" }

beacon_node/http_api/tests/tests.rs

@@ -8,7 +8,7 @@ use discv5::enr::{CombinedKey, EnrBuilder};
 use environment::null_logger;
 use eth2::Error;
 use eth2::StatusCode;
-use eth2::{types::*, BeaconNodeHttpClient, Url};
+use eth2::{types::*, BeaconNodeHttpClient};
 use eth2_libp2p::{
     rpc::methods::MetaData,
     types::{EnrBitfield, SyncState},
@@ -18,6 +18,7 @@ use futures::stream::{Stream, StreamExt};
 use futures::FutureExt;
 use http_api::{Config, Context};
 use network::NetworkMessage;
+use sensitive_url::SensitiveUrl;
 use slot_clock::SlotClock;
 use state_processing::per_slot_processing;
 use std::convert::TryInto;
@@ -200,7 +201,7 @@ impl ApiTester {
         tokio::spawn(async { server.await });
 
         let client = BeaconNodeHttpClient::new(
-            Url::parse(&format!(
+            SensitiveUrl::parse(&format!(
                 "http://{}:{}",
                 listening_socket.ip(),
                 listening_socket.port()
@@ -307,7 +308,7 @@ impl ApiTester {
         tokio::spawn(async { server.await });
 
         let client = BeaconNodeHttpClient::new(
-            Url::parse(&format!(
+            SensitiveUrl::parse(&format!(
                 "http://{}:{}",
                 listening_socket.ip(),
                 listening_socket.port()