Make it possible to specify BR format in query string

instead of

curl -H 'accept: application/obs+xml' https://br.opensuse.org/status/Java:packages/jameica
curl -H 'accept: application/json' https://br.opensuse.org/status/Java:packages/jameica

this can be used

curl https://br.opensuse.org/status/Java:packages/jameica?format=xml
curl https://br.opensuse.org/status/Java:packages/jameica?format=json

which provides much simpler and easier to understand interface.

Fixes: #94

obs-status-service/main.go

@@ -275,7 +275,7 @@ func main() {
 		res.Write([]byte("404 page not found\n"))
 	})
 	http.HandleFunc("GET /status/{Project}", func(res http.ResponseWriter, req *http.Request) {
-		mime := ParseMimeHeader(req)
+		mime := ParseMimeHeaderAndQuery(req)
 		obsPrj := req.PathValue("Project")
 		common.LogInfo("  GET /status/"+obsPrj, "["+mime.MimeType()+"]")
 
@@ -296,7 +296,7 @@ func main() {
 		}
 	})
 	http.HandleFunc("GET /status/{Project}/{Package}", func(res http.ResponseWriter, req *http.Request) {
-		mime := ParseMimeHeader(req)
+		mime := ParseMimeHeaderAndQuery(req)
 		obsPrj := req.PathValue("Project")
 		obsPkg := req.PathValue("Package")
 		common.LogInfo("  GET /status/"+obsPrj+"/"+obsPkg, "["+mime.MimeType()+"]")
@@ -326,7 +326,7 @@ func main() {
 
 	})
 	http.HandleFunc("GET /status/{Project}/{Package}/{Repository}", func(res http.ResponseWriter, req *http.Request) {
-		mime := ParseMimeHeader(req)
+		mime := ParseMimeHeaderAndQuery(req)
 		obsPrj := req.PathValue("Project")
 		obsPkg := req.PathValue("Package")
 		repo := req.PathValue("Repository")
@@ -355,7 +355,7 @@ func main() {
 		}
 	})
 	http.HandleFunc("GET /status/{Project}/{Package}/{Repository}/{Arch}", func(res http.ResponseWriter, req *http.Request) {
-		mime := ParseMimeHeader(req)
+		mime := ParseMimeHeaderAndQuery(req)
 		prj := req.PathValue("Project")
 		pkg := req.PathValue("Package")
 		repo := req.PathValue("Repository")

obs-status-service/mimeheader.go

@@ -21,7 +21,16 @@ var AcceptedStatusMimes []string = []string{
 	XmlMime,
 }
 
-func ParseMimeHeader(req *http.Request) *MimeHeader {
+func ParseMimeHeaderAndQuery(req *http.Request) *MimeHeader {
+	format := req.URL.Query().Get("format")
+	switch format {
+	case "svg":
+		return &MimeHeader{MimeHeader: SvgMime}
+	case "json":
+		return &MimeHeader{MimeHeader: JsonMime}
+	case "xml":
+		return &MimeHeader{MimeHeader: XmlMime}
+	}
 	proposedMimes := req.Header.Values("Accept")
 	mime := MimeHeader{MimeHeader: SvgMime}
 	if len(proposedMimes) == 0 {