Update docs

[phzietsman]

Docs are missing the following

• All the code snippets in the docs have incorrect syntax for terraform 0.12+.
• Import examples
• provider usage sample is incorrect, baseurl needs a trailing /

Terraform Version

terraform v0.12+

Affected Resource(s)

All

Terraform Configuration Files

As an example:

data "gocd_job_definition" "test" {
 ...

  tabs = [
    {
      name = "Report"
      path = "report1.html"
    },
  ]

  artifacts = [
    {
      type   = "build"
      source = "web.war"
    },
  ]
}

Should be:

data "gocd_job_definition" "test" {
 ...

  tabs {
      name = "Report"
      path = "report1.html"
  }

  artifacts {
      type   = "build"
      source = "web.war"
  }
}