WP Optimize Premium 4.1.1

* FIX: Cache - Warning failed to open dir
* FIX: Premium - Unused images - Fixed issue with images including a size suffix similar to WP sizes
* FIX: Display optimization data based on retention period
* FIX: Scheduled cleanup settings - Invalid date selection
* TWEAK: Premium - Separate table optimisations per sub-site
* TWEAK: Premium - Unused images - Add compatibilty with the Envira Gallery plugin
* TWEAK: Page caching: add support for Avada
* TWEAK: Add visual clue when image compression was cancelled
* TWEAK: Image compression - multi image selection using Ctrl/Shift keys
* TWEAK: Premium - Unused images - Reset last clicked image reference when `select none` is clicked
* TWEAK: Prevent bots from indexing plugins list json file
* TWEAK: Minify - Added a setting to change the time stale cache should be kept
* TWEAK: Better support for Beaver Builder
* TWEAK: Prevent PHP warning when reading a file's size
* TWEAK: Cache - Purge the blog page when updating a post
* TWEAK: Cache - Purge next and previous posts on post update
* TWEAK: Cache - Purge sitemap files on post update

* FEATURE: Premium - Preload key requests (Preload fonts and other assets)
* FIX: Detecting Brotli compression issue
* FIX: Cache - PHP Warning in URLs to exclude from caching
* FIX: Premium - Unused images - Unused Images Tool not recognising Greek characters
* FIX: Button for disabling Gzip doesn't showing
* TWEAK: Database optimization - Prevent fatal error due to files missing
* TWEAK: Skip minify when SCRIPT_DEBUG is set to true
* TWEAK: Fixed Font-awesome settings
* TWEAK: Add support for different spellings of "Font-awesome"
* TWEAK: Update the feature comparison table
* TWEAK: Added the option to not show the warning before deleting a table
* TWEAK: Wipe all options upon plugin de-installation
* TWEAK: Premium - Lazy-load - Lazy load support for background images
* TWEAK: Minify - Add file size in the minify cache summary
* TWEAK: Detect conflicting plugins for GZIP issue
* TWEAK: Database optimization - Include all tables if database prefix is not set on WP install
* TWEAK: Premium - Unused images - added "X of X images loaded" for unused trash images
* TWEAK: Don't allow to remove actionscheduler_* tables
* TWEAK: Premium - Unused images - Show a progression screen when doing any action with unused images
* TWEAK: Cache - Enable cache for the old default permalink structure `domain.com/index.php/a-post-name` by creating a folder without the extention
* TWEAK: Show previous action as message on Trackbacks or Comments enable or disable.
* TWEAK: Prevent deprecation notice on PHP 8.0
* TWEAK: Update notices

* FIX: Fix wrong class name