Upgrade from futures-preview to futures 0.3.1, and remove futures 0.1 where currently possible (#4083)

* Migrate node and node-template

* Migrate srml

* Simple changes

* Add async-std for interval

* Fix test-runtime warning

* Small changes

* move futures01 in core/rpc to dev-deps

* Change wasm CI builds

* Switch to async-std 1.0.1

* Remove async-std dep of network

* Add modified lockfile

* Fix node cli browser build

* Remove authority-discovery async-std dep

* Add Send + Sync to interval dyn stream

substrate/client/network/src/utils.rs

@@ -0,0 +1,25 @@
+// Copyright 2019 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+use std::time::Duration;
+use futures03::{FutureExt, Stream, StreamExt, stream::unfold};
+use futures_timer::Delay;
+
+pub fn interval(duration: Duration) -> impl Stream<Item=()> + Unpin {
+	unfold((), move |_| {
+		Delay::new(duration).map(|_| Some(((), ())))
+	}).map(drop)
+}