User-Agent uses the Go user agent instead of the Terraform user-agent

[awilliamsOM1]

Terraform uses a user agent that looks like this:

User-Agent: Terraform/0.12.6 TF_APPEND_USER_AGENT where TF_APPEND_USER_AGENT is an optional environment variable.

The keycloak provider in terraform does not specify the user agent when making requests so the default GO user agent is used User-Agent: Go-http-client/1.1

This causes problems for because we cannot properly identify traffic as coming from terraform. The standard terraform user agent should be used possibly with other provider information added