GUACAMOLE-773: Remove angular-touch (no longer applicable).

Previously, the angular-touch library provided by AngularJS was used to
allow click interactions with UI components to work on touch devices
without an uncomfortable ~300ms delay. From AngularJS 1.7.x onward, this
feature of angular-touch is no longer present:

https://docs.angularjs.org/guide/migration#ngtouch

This should be OK - modern browsers will now recognize applications
aimed at touch support via the use of the "viewport" meta tag (which we
use), removing our original need for angular-touch. The same goes for
IE10+.

guacamole/src/main/frontend/package.json

@@ -8,7 +8,6 @@
         "angular": "1.8.2",
         "angular-route": "1.8.2",
         "angular-templatecache-webpack-plugin": "^1.0.1",
-        "angular-touch": "1.8.2",
         "angular-translate": "2.18.4",
         "angular-translate-interpolation-messageformat": "2.18.4",
         "angular-translate-loader-static-files": "2.18.4",