Fixes a number of issues with the image uploader. Read below,

- Added a remove link to remove files that have an error.
- Error will appear below the progress bar.
- Hovering on dz-image or dz-details will display the error message. Otherwise error message was covering the remove link as well.
- Removed styling around the file size.
- Removed gradient effect in accordance with BookStack styling.
- Dropzone filenae will not overflow the container element. Also done for page attachments
- Added a 'uploaded' error message. this error was being thrown when the file size exceeded the server configured file size. (https://stackoverflow.com/a/42934387/903324)

Towards #741

Signed-off-by: Abijeet <abijeetpatro@gmail.com>

resources/lang/en/errors.php

@@ -35,6 +35,7 @@ return [
     'cannot_get_image_from_url' => 'Cannot get image from :url',
     'cannot_create_thumbs' => 'The server cannot create thumbnails. Please check you have the GD PHP extension installed.',
     'server_upload_limit' => 'The server does not allow uploads of this size. Please try a smaller file size.',
+    'uploaded'  => 'The server does not allow uploads of this size. Please try a smaller file size.',
     'image_upload_error' => 'An error occurred uploading the image',
     'image_upload_type_error' => 'The image type being uploaded is invalid',
 
@@ -78,4 +79,4 @@ return [
     'error_occurred' => 'An Error Occurred',
     'app_down' => ':appName is down right now',
     'back_soon' => 'It will be back up soon.',
-];
+];