Transfer Panel Details Without an Extra Layer of JSON Encoding (#14)

**Rationale:**

This made it harder to snoop on the traffic in the network monitor because it was encoded as a string.

**Changes:**

- Backend now accepts & provides the panel data as a JSON object rather than as a string
- Backend now supports compression
- Minor improvements to error handling
- Some panel structures were getting saved in the JSON when they weren't supposed to be (now this no longer happens)

Reviewed-on: #14
Co-authored-by: Sergey Savelyev <sergeysav.nn@gmail.com>
Co-committed-by: Sergey Savelyev <sergeysav.nn@gmail.com>

server/src/http/mod.rs

@@ -9,7 +9,7 @@ use crate::http::backend::setup_backend;
 use crate::http::websocket::setup_websocket;
 use crate::panels::PanelService;
 use crate::telemetry::management_service::TelemetryManagementService;
-use actix_web::middleware::Logger;
+use actix_web::middleware::{Compress, Logger};
 use actix_web::{web, App, HttpServer};
 use log::info;
 use std::sync::Arc;
@@ -36,6 +36,7 @@ pub async fn setup(
             .service(web::scope("/backend").configure(setup_backend))
             .service(web::scope("/ws").configure(setup_websocket))
             .service(web::scope("/api").configure(setup_api))
+            .wrap(Compress::default())
             .wrap(Logger::default())
     })
     .bind("localhost:8080")?