Add Yandex Cloud service DNS API

[statkashaman]

DNS API for https://cloud.yandex.ru/ DNS Service.

To authorize in the api, you need a file of the private key of the service account, since the current CI does not provide for forwarding the file, I corrected the CI by adding the echo of the key to the file.

[Neilpang]

please rebase code and check this guide: https://github.com/acmesh-official/acme.sh/wiki/DNS-API-Dev-Guide