Add HashiCorp Nomad provider (#483)

* provider: adding Nomad provider

* updating CONTRIBUTING.md with Nomad provider

* updated README.md by adding the Nomad provider

* fix typo

* adding nomad/api and nomad/testutil deps

* adding Nomad binary dependency for provider tests

* fixed the nomad binary download command step and added tolerations to the nomad provider.

* adding nomad provider demo gif

* adding my name to authors

* adding two missing go-rootcerts files after dep ensure

* delete pod comment

vendor/github.com/mitchellh/reflectwalk/location_string.go

@@ -0,0 +1,16 @@
+// Code generated by "stringer -type=Location location.go"; DO NOT EDIT.
+
+package reflectwalk
+
+import "fmt"
+
+const _Location_name = "NoneMapMapKeyMapValueSliceSliceElemArrayArrayElemStructStructFieldWalkLoc"
+
+var _Location_index = [...]uint8{0, 4, 7, 13, 21, 26, 35, 40, 49, 55, 66, 73}
+
+func (i Location) String() string {
+	if i >= Location(len(_Location_index)-1) {
+		return fmt.Sprintf("Location(%d)", i)
+	}
+	return _Location_name[_Location_index[i]:_Location_index[i+1]]
+}