Update error message and gofmt clean up for Go 1.17

Allow users of resolver pkg to check for servfail

add version info

check for constraints in tlsa filter

update readme

Add parameter to the resolver's LookupIP method to exclude non authen…

…ticated responses.

Switch to goproxy it's lightweight, appears to be more maintained, and doesn't break web sockets.
Avoid doing TLSA lookups if no authenticated IP addresses are available.
Send the authenticated response via proxy context to dialTLS in HTTP transport.
Move proxy details to proxy.go and use the cmd app only to configure and start godane.
Encrypt the private key

first commit