Add a browser-utils crate (#4394)

* Squash

* Fix keystore on wasm

* Update utils/browser/Cargo.toml

Co-Authored-By: Benjamin Kampmann <ben@gnunicorn.org>

* export console functions

* Use an Option<PathBuf> in keystore instead of cfg flags

* Add a KeystoreConfig

* Update libp2p

* Bump kvdb-web version

* Fix cli

* Upgrade versions

* Update wasm-bindgen stuff

Co-authored-by: Benjamin Kampmann <ben.kampmann@googlemail.com>

substrate/bin/node/cli/browser-demo/build.sh

@@ -1,3 +1,3 @@
 #!/usr/bin/env sh
 wasm-pack build --target web --out-dir ./browser-demo/pkg --no-typescript --release ./.. -- --no-default-features --features "browser"
-python -m SimpleHTTPServer 8000
+python -m http.server 8000

substrate/bin/node/cli/browser-demo/index.html

@@ -19,7 +19,7 @@ async function start() {
 
 	// Build our client.
 	log('Starting client');
-	let client = start_client(ws());
+	let client = await start_client(ws());
 	log('Client started');
 
 	client.rpcSubscribe('{"method":"chain_subscribeNewHead","params":[],"id":1,"jsonrpc":"2.0"}',
@@ -29,7 +29,7 @@ async function start() {
 		client
 			.rpcSend('{"method":"system_networkState","params":[],"id":1,"jsonrpc":"2.0"}')
 			.then((r) => log("Network state: " + r));
-	}, 1000);
+	}, 20000);
 }
 
 start();