Remove all fmt and stdlib log statements in favor of appropriate Logrus calls

[trevrosen]

There are lots of print statements left over from debugging that ought to be changed into proper logging statements. Change to structured logging and remove redundant newlines.

Example:

appoptics-api-go/client.go

Line 221 in 917bbb9

fmt.Printf("response body: %s\n\n", string(buf.Bytes()))