Blessing Skin Server v3.0.3

[New] Option for setting score of private textures
[New] Use sweetalert2 to show message in some cases
[New] Customization of copyright text
[New] Rules of mime type for IIS
[New] Logging in with your owned player names
[New] Migration for v2 users
[Fix] Set default timezone when boot up
[Fix] Relative urls, close #27
[Fix] Default value of some columns
[Fix] Escaping custom css/js
[Fix] Calculating total pages
[Improved] use css to cut texture name
[Improved] Notify user if texture file is invalid, or delete automatically