Check DNS over HTTPS implementation

Implemented in: https://0xacab.org/leap/bitmask-core/-/blob/5257704e8d0447f7528a59f75ddec8a161482635/pkg/bootstrap/doh.go Questions:

• Does it use a http timeout?
• Does the code verify the ssl certificate? There is only an IP address

  • openDNSResolver = "208.67.222.222"``openDNSResolver = "208.67.222.222"

• also use multiple provider, if one fails.