Drupal 10 compatibility

There are a few occurrences in the code that needs patched before this module supports Drupal 10.

We're already using ^8.9 || ^9 which means all our used Drupal classes should be found in 8.9, the lowest version that we support, if they are present in 9.x.

Here's a current list found through the "Inspect code"functionality in PHP Storm:

• file_save_data() is replaced with \Drupal::service('file.repository')->writeData()
• module_load_include is replaced with \Drupal::moduleHandler()->loadInclude()
• There were also two references to non-existent classes in the comments: Twig_Environment and MimeTypeGuesserInterface
• We need to bump the version requirement to ^8.9 || ^9 || ^10