Add raw blob endpoint to get objects by SHA ID (#5334)

* Add raw blob endpoint

This should make it possible to download raw blobs directly from
/:repo/:username/raw/blob/:sha1 URLs.

* fix: Make it work

* As an SHA-ID is no path getRefNameFromPath can't be used to verify
file specifying parameter
* added relevant change in go-gitea/git #132

Signed-off-by: Berengar W. Lehr <Berengar.Lehr@kompetenztest.de>

* Update Gopkg.lock

Can't update all vendors due to errors

Signed-off-by: Berengar W. Lehr <Berengar.Lehr@kompetenztest.de>

* style: Add Gitea copyright header

* feat: Added integration test for /repo/u/r/raw/blob

* fix: correct year in copyright header

integrations/download_test.go

@@ -0,0 +1,24 @@
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package integrations
+
+import (
+	"net/http"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDownloadByID(t *testing.T) {
+	prepareTestEnv(t)
+
+	session := loginUser(t, "user2")
+
+	// Request raw blob
+	req := NewRequest(t, "GET", "/user2/repo1/raw/blob/4b4851ad51df6a7d9f25c979345979eaeb5b349f")
+	resp := session.MakeRequest(t, req, http.StatusOK)
+
+	assert.Equal(t, "# repo1\n\nDescription for repo1", resp.Body.String())
+}