Hosted counter example (#38)

* Create `hosted-counter` example

* Use `linera-protocol` with faucet client crate

* Request application

* Bump `linera-protocol`

* `examples/hosted-counter`: tweak styling

* Cleanup

* Bump `linera-protocol`

This allows us to remove the logic around requesting applications,
since linera-io/linera-protocol#3382 makes
this transparent.

* `examples/hosted-counter`: externalize `@linera/client`

* `hosted-counter`: port to mininet

* `hosted-counter`: make more mobile-friendly

* `examples/hosted-counter`: mobile improvements

* `linera-protocol`: avoid deadlocking when reaping tasks

* `examples`: abstract out stylesheet

* `client`: improve error reporting

* Clippy clean the client library

* Fix extension build

* Address review comments

Author: Twey

client/.cargo/config.toml

@@ -1,5 +1,11 @@
 [target.wasm32-unknown-unknown]
-rustflags = ["-C", "target-feature=+atomics,+bulk-memory,+mutable-globals"]
+rustflags = [
+    # support threading
+    "-C", "target-feature=+atomics,+bulk-memory,+mutable-globals",
+    # allow linking C code (for `rust_secp256k1`)
+    "--cfg=web_sys_unstable_apis",
+    "-Z", "wasm_c_abi=spec",
+]
 
 [unstable]
 build-std = ["panic_abort", "std"]