feat: add podcast banner field for each podcast + refactor images configuration

- rename image fields on podcast, episode and persons for better clarity
- set different sizes
config for podcast cover, banner and persons avatars
- add tiny size for covers
- fix responsive
on admin forms

modules/Admin/Language/en/Validation.php

@@ -11,8 +11,8 @@ declare(strict_types=1);
 return [
     'min_dims' =>
         '{field} is either not an image, or it is not wide or tall enough.',
-    'is_image_squared' =>
-        '{field} is either not an image, or it is not squared (width and height differ).',
+    'is_image_ratio' =>
+        '{field} is either not an image or not of the right ratio.',
     'validate_url' =>
         'The {field} field must be a valid URL (eg. https://example.com/).',
 ];