refactor(challenge): change mention of "challenge" to "mission"

the only mentions of "challenge" is for the "user-challenge.json" file

deadlock-plugins/deadlock-extension/docs/README.md

 # Deadlock Coding
 
-Vscode extension to show a panel with :
+VSCode extension to show a panel with :
 
-- adresses availables for the current challenge pulled from `/home/config/user-challenge.json`
-- challenge instruction pulled from the `README.md`
+- adresses availables for the current mission pulled from `/home/config/user-challenge.json`
+- mission instruction pulled from the `README.md`
 
 ## Quick start
 
-- Run `setup-dev-env.sh` to mock challenge configuration
+- Run `setup-dev-env.sh` to mock mission configuration
 - Run `install.sh`
 - Run `build.sh`
 - Press `F5` (or use `Run and Debug` tab).

deadlock-plugins/deadlock-extension/src/customTypings/HttpStatusCode.ts

@@ -158,7 +158,7 @@ export enum HttpStatusCode {
 
   /**
    * Similar to 403 Forbidden, but specifically for use when authentication is required and has failed or has not yet
-   * been provided. The response must include a WWW-Authenticate header field containing a challenge applicable to the
+   * been provided. The response must include a WWW-Authenticate header field containing a mission applicable to the
    * requested resource. See Basic access authentication and Digest access authentication. 401 semantically means
    * "unauthenticated",i.e. the user does not have the necessary credentials.
    */

deadlock-plugins/deadlock-extension/src/view/briefingView.ts

@@ -89,7 +89,7 @@ export default class BriefingView extends WebviewBase {
     output += '<br/>';
 
     if (userConfig.getUsername()) {
-      output += this.renderUserChallengeConfig();
+      output += this.renderUserMissionConfig();
     } else {
       output += 'Loading help..';
     }
@@ -97,7 +97,7 @@ export default class BriefingView extends WebviewBase {
     return output;
   }
 
-  private renderUserChallengeConfig() {
+  private renderUserMissionConfig() {
     let adresses = '';
 
     let pathsLength = 0;
@@ -116,7 +116,7 @@ export default class BriefingView extends WebviewBase {
 
     if (pathsLength > 0) {
       return `<h3>Configuration</h3>
-      You have the following adresses availables for your challenge : <ul>${adresses}</ul>
+      You have the following adresses availables for your mission : <ul>${adresses}</ul>
       </br>
       You also have access to these paths from:
       <ul>