added setComponents to get access to services

I didn't find a way to get access to functions from the services (like getVideoUrl) on API/PHP level, so I added the setComponents function to define a method to call them;

```
use nystudio107\transcoder\Transcoder;

// where $video is the reference to the asset

$encodedVideoUrl = Transcoder::$plugin->get->getVideoUrl($video, []); 
$encodedThumbnail = Transcoder::$plugin->get->getVideoThumbnailUrl($video, [
    'width' => 800,
    'height' => 450,
    'timeInSecs' => 5
]);
```
This seem to work now.

Author: arifje

src/Transcoder.php

@@ -57,6 +57,11 @@ public function init()
         parent::init();
         self::$plugin = $this;
 
+        // Load plugin components
+        $this->setComponents([
+            'get' => Transcode::class
+        ]);
+
         // Register our variables
         Event::on(
             CraftVariable::class,