fix: fix some crashes caused by improper JSON validation

[Flechaa]

This PR fixes two issues:

• JSON messages sent after the device welcome message could have errors and they are not caught:
  

  Rotom/packages/connections/src/lib/deviceControlConnection.ts

  Lines 78 to 120 in e5074b4

  	received(message: string) {
  	this.log.debug(`${this.deviceId}: <MITMC ${message}`);
  	this.dateLastMessageReceived = Date.now();
  	this.dateLastMessageSent = Date.now();
  	if (this.init) {
  	try {
  	const id = JSON.parse(message);
  	this.deviceId = id.deviceId;
  	this.version = id.version;
  	this.origin = id.origin;
  	this.publicIp = id.publicIp;
  	this.noMessagesSent = 0;
  	this.noMessagesReceived = 0;
  	this.responses = {};
  	} catch (e) {
  	this.log.error(`Device /control - error decoding welcome message, disconnecting`);
  	this.ws.close();
  	return;
  	}
  	this.emit('init', this, message);
  	this.init = false;
  	} else {
  	const response = JSON.parse(message.toString());
  	const promise = this.responses[response.id];
  	if (promise) {
  	delete this.responses[response.id];
  	if (response.status == 200) {
  	this.log.debug(`${this.deviceId}: <MITMC Received job response message ${message.toString()}`);
  	promise.resolve(response.body);
  	} else {
  	this.log.warn(`${this.deviceId}: <MITMC Received rejection message ${message.toString()}`);
  	promise.reject(`Status ${response.status} ${response.body?.errorReason ?? ''}`);
  	}
  	} else {
  	this.log.warn(`${this.deviceId}: <MITMC Unrecognized response ${message.toString()}`);
  	}
  	}
  	}

  
  Crash example:

const WebSocket = require("ws");

const ws = new WebSocket("ws://localhost:7070/control", {
    headers: {
        "x-rotom-secret": ""
    }
});

ws.on("open", () => {
    ws.send("{}");
    ws.send("");
});

• If getMemoryUsage response does not have a body, it will cause the lastMemory property to be set to undefined:

  Rotom/packages/connections/src/lib/deviceControlConnection.ts

  Line 160 in e5074b4

  this.lastMemory = memory; // spy on result

  
  Which will cause the process to crash later in this line:

  Rotom/packages/server/src/index.ts

  Line 371 in e5074b4

  const { memMitm, memFree, memStart } = connection.lastMemory;

  
  Crash example (takes 60 seconds to crash):

const WebSocket = require("ws");

const ws = new WebSocket("ws://localhost:7070/control", {
    headers: {
        "x-rotom-secret": ""
    }
});

ws.on("open", () => {
    ws.send("{}");
});

ws.on("message", (message) => {
    console.log(message.toString());
    const req = JSON.parse(message);
    ws.send(JSON.stringify({ id: req.id, status: 200 }));
});

[jfberry]

Thanks for this - it's always good to harden!
It looks good to me, but I will defer to @na-ji on typescript style issues :-)

[na-ji]

Thanks!