Feature: #79124 - Allow overwriting of template paths in BackendTemplateView

See Issue #79124

Description

BackendTemplateView now allows overwriting of template paths to add your own locations for templates, partials and layouts in a BackendTemplateView based backend module.

Impact

You can now do for example

$frameworkConfiguration = $this->configurationManager->getConfiguration(ConfigurationManagerInterface::CONFIGURATION_TYPE_FRAMEWORK);
$viewConfiguration = [
   'view' => [
      'templateRootPaths' => ['EXT:myext/Resources/Private/Backend/Templates'],
      'partialRootPaths' => ['EXT:myext/Resources/Private/Backend/Partials'],
      'layoutRootPaths' => ['EXT:myext/Resources/Private/Backend/Layouts'],
   ],
];
$this->configurationManager->setConfiguration(array_merge($frameworkConfiguration, $viewConfiguration));