Replace gRPC Backend (#10)

**Rationale:**

Having two separate servers and communication methods resulted in additional maintenance & the need to convert often between backend & frontend data types.
By moving the backend communication off of gRPC and to just use websockets it both gives more control & allows for simplification of the implementation.

#8

**Changes:**

- Replaces gRPC backend.
  - New implementation automatically handles reconnect logic
- Implements an api layer
- Migrates examples to the api layer
- Implements a proc macro to make command handling easier
- Implements unit tests for the api layer (90+% coverage)
- Implements integration tests for the proc macro (90+% coverage)

Reviewed-on: #10
Co-authored-by: Sergey Savelyev <sergeysav.nn@gmail.com>
Co-committed-by: Sergey Savelyev <sergeysav.nn@gmail.com>

server/src/command/command_handle.rs

@@ -0,0 +1,20 @@
+use uuid::Uuid;
+
+pub struct CommandHandle {
+    name: String,
+    uuid: Uuid,
+}
+
+impl CommandHandle {
+    pub fn new(name: String, uuid: Uuid) -> Self {
+        Self { name, uuid }
+    }
+
+    pub fn name(&self) -> &str {
+        &self.name
+    }
+
+    pub fn uuid(&self) -> &Uuid {
+        &self.uuid
+    }
+}