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/offchain/Cargo.toml

@@ -12,8 +12,8 @@ client-api = { package = "substrate-client-api", path = "../api" }
 sr-api = { path = "../../primitives/sr-api" }
 fnv = "1.0.6"
 futures01 = { package = "futures", version = "0.1" }
-futures-preview = "0.3.0-alpha.19"
-futures-timer = "0.4.0"
+futures = "0.3.1"
+futures-timer = "2.0"
 log = "0.4.8"
 threadpool = "1.7"
 num_cpus = "1.10"