TYPO3 CMS v8 Support

• Support for TYPO3 7.6 - 8.5.0-dev
• composer.json improvements
• fixed exception (Please review them exactly - it's the first time I'm working with TYPO3 backend modules)
• removed obsolete TER-v1 ext_emconf.php options

I look forward to get some feedback ¯_(ツ)_/¯

Classes/ViewHelpers/AbstractViewHelper.php

@@ -36,20 +36,10 @@ class AbstractViewHelper extends AbstractBackendViewHelper {
 	/**
 	 * Returns an instance of the page renderer
 	 *
-	 * @deprecated Implement the following migration if the extension just needs to support > 7.5.
 	 * @return PageRenderer
 	 */
 	public function getPageRenderer() {
-//		Migration
-//		return $this->objectManager->get(\TYPO3\CMS\Core\Page\PageRenderer::class);
-		if (TYPO3_MODE === 'BE') {
-			$pageRenderer = $this->getDocInstance()->getPageRenderer();
-		} else {
-			/** @noinspection PhpUndefinedMethodInspection */
-			$pageRenderer = $GLOBALS['TSFE']->getPageRenderer();
-		}
-
-		return $pageRenderer;
+		return $this->objectManager->get(\TYPO3\CMS\Core\Page\PageRenderer::class);
 	}
 
 	/**
@@ -70,4 +60,4 @@ class AbstractViewHelper extends AbstractBackendViewHelper {
 	}
 }
 
-?>
\ No newline at end of file
+?>