Initial merge of faas-containerd

This patch completes part of the work in #20 by porting the code
for faas-containerd in-tree. When tested, I was able to deploy
and then remove figlet from the store on `x86_64`.

In a follow-up PR, duplication will be removed where possible
and consolidated with updated documentation.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

pkg/provider/handlers/info.go

@@ -0,0 +1,43 @@
+package handlers
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/openfaas/faas-provider/types"
+)
+
+const (
+	//OrchestrationIdentifier identifier string for provider orchestration
+	OrchestrationIdentifier = "containerd"
+	//ProviderName name of the provider
+	ProviderName = "faas-containerd"
+)
+
+//MakeInfoHandler creates handler for /system/info endpoint
+func MakeInfoHandler(version, sha string) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if r.Body != nil {
+			defer r.Body.Close()
+		}
+
+		infoResponse := types.InfoResponse{
+			Orchestration: OrchestrationIdentifier,
+			Provider:      ProviderName,
+			Version: types.ProviderVersion{
+				Release: version,
+				SHA:     sha,
+			},
+		}
+
+		jsonOut, marshalErr := json.Marshal(infoResponse)
+		if marshalErr != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusOK)
+		w.Write(jsonOut)
+	}
+}