Add safe search feature to Coc Coc

[hncomputer1993]

• Hello everyone and the AdGuard Home development team. I am very happy to know you and the application! I really love and appreciate the value that AdGuard brings, it is truly priceless!

• As a user of the AdGuard Home DNS application. I have a few contributions, hope they will be approved!

1. "Force safe search" option, need to add Coc Coc's search server (https://coccoc.com/search) and Yahoo (search.yahoo.com)
2. "Encryption settings" option, if possible, I really hope there can be more customizations. (Port 443 access /dns-query and add web admin portal will increase security! My personal opinion is that /dns-query port and website admin portal are 2 separate ports)