Preparing backend to receive data from shards (#337)

* Move backend to backend/core

* Ported shard receiver WIP

* Remove dead code

backend/Cargo.lock

@@ -340,6 +340,15 @@ version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "904dfeac50f3cdaba28fc6f57fdcddb75f49ed61346676a78c4ffe55877802fd"
 
+[[package]]
+name = "bincode"
+version = "1.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b1f45e9417d87227c7a56d22e471c6206462cba514c7590c09aff4cf6d1ddcad"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "bitflags"
 version = "1.2.1"
@@ -1688,6 +1697,7 @@ dependencies = [
  "actix-http",
  "actix-web",
  "actix-web-actors",
+ "bincode",
  "bytes",
  "chrono",
  "clap",
@@ -1703,6 +1713,7 @@ dependencies = [
  "serde",
  "serde_json",
  "simple_logger",
+ "thiserror",
 ]
 
 [[package]]
@@ -1737,6 +1748,26 @@ dependencies = [
  "unicode-width",
 ]
 
+[[package]]
+name = "thiserror"
+version = "1.0.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e0f4a65597094d4483ddaed134f409b2cb7c1beccf25201a9f73c719254fa98e"
+dependencies = [
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "1.0.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7765189610d8241a44529806d6fd1f2e0a08734313a35d5b3a556f92b381f3c0"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "thread_local"
 version = "1.0.1"