Add riot-desktop shortcuts for forward/back matching browsers&slack

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/electron-main.js

@@ -295,6 +295,16 @@ ipcMain.on('ipcCall', async function(ev, payload) {
         case 'getConfig':
             ret = vectorConfig;
             break;
+        case 'navigateBack':
+            if (mainWindow.webContents.canGoBack()) {
+                mainWindow.webContents.goBack();
+            }
+            break;
+        case 'navigateForward':
+            if (mainWindow.webContents.canGoForward()) {
+                mainWindow.webContents.goForward();
+            }
+            break;
         case 'setLanguage': {
             // work around `setSpellCheckerLanguages` being case-sensitive by converting to expected case
             const caseMap = {};