Add support and documentation to use API keys (#724)

Simplify the API by adding a helper function to set the JWT only with kuzzle API key format.

Author: ScreamZ

doc/7/controllers/auth/create-api-key/snippets/create-api-key.js

@@ -18,6 +18,9 @@ try {
   */
 
   console.log('API key successfully created');
+
+  // Then use it with your client. Note: You don't need to call login after this because this bypasses the authentication system.
+  kuzzle.setAPIKey(apiKey._source.token)
 } catch (e) {
   console.error(e);
 }

src/Kuzzle.ts

@@ -620,6 +620,19 @@ export class Kuzzle extends KuzzleEventEmitter {
     return this.protocol.connect();
   }
 
+  /**
+   * Set this client to use a specific API key.
+   *
+   * After doing this you don't need to use login as it bypasses the authentication process.
+   */
+  public setAPIKey(apiKey: string) {
+    if (apiKey.match(/^kapikey-/) === null) {
+      throw new Error("Invalid API key. Missing the `kapikey-` prefix.");
+    }
+
+    this.jwt = apiKey;
+  }
+
   async _reconnect() {
     if (this._reconnectInProgress) {
       return;