Update how the node SDK handles self signed requests

The NODE_TLS_REJECT_UNAUTHORIZED env variable will disable SSL checks
for all requests. This PR changes the node SDK to only disable SSL
checks for Appwrite related requests by passing an option to axios.

Author: stnguyen90

templates/node/lib/client.js.twig

@@ -1,5 +1,6 @@
 const os = require('os');
 const URL = require('url').URL;
+const https = require("https");
 const axios = require('axios');
 const FormData = require('form-data');
 const {{spec.title | caseUcfirst}}Exception = require('./exception.js');
@@ -81,11 +82,6 @@ class Client {
     }
 
     async call(method, path = '', headers = {}, params = {}, responseType = 'json') {
-        if(this.selfSigned) { // Allow self signed requests
-            process.env["NODE_TLS_REJECT_UNAUTHORIZED"] = 0;
-        }
-
-
         headers = Object.assign({}, this.headers, headers);
 
         let contentType = headers['content-type'].toLowerCase();
@@ -125,6 +121,10 @@ class Client {
             json: (contentType.startsWith('application/json')),
             responseType: responseType
         };
+        if (this.selfSigned) {
+            // Allow self signed requests
+            options.httpsAgent = new https.Agent({ rejectUnauthorized: false });
+        }
         try {
             let response = await axios(options);
             return response.data;