Added command file and skeleton for methods
Merged code from @benmay, would have liked to merge his commit but time aint on my side
Cleaned up error
Added the regenerate --id=
Removed unused coded and the bla
Cleanup before pull request and add props to Viperbond007
Added confirmation check before regenerating all images
Skip confirmation if `id` arg is given
First start better naming
Optimizing looping and unlinking of the resized images
make update-phar generate a checksum

[ci skip]
Removed use of $error
Removed settings timeout
Use concate instead of sprintf
Using WP_CLI::warning
Using WP_CLI::warning
Polished some feedback messages
Cleaned up unused code
Better grammar
Fixed variable name so thumbnails get unlinked again