Fix: Storage leak in Builder and Fetcher (#2979)

* Fix storage leak in builder
```
builder pod keeps old src and deployment packages irrespective of build status.
delete src package after every build request is completed.
delete deployment package after package is uploaded.
```
* Optimized src/deploy cleanup pkg code
* Fix high severity security issue
* Add a test for builder's Clean API
* Resolve review comments

---------

Signed-off-by: Md Soharab Ansari <soharab.ansari@infracloud.io>

pkg/fetcher/fetcher.go

@@ -525,6 +525,14 @@ func (fetcher *Fetcher) UploadHandler(w http.ResponseWriter, r *http.Request) {
 	srcFilepath := filepath.Join(fetcher.sharedVolumePath, req.Filename)
 	dstFilepath := filepath.Join(fetcher.sharedVolumePath, zipFilename)
 
+	defer func() {
+		errC := utils.DeleteOldPackages(srcFilepath, "DEPLOY_PKG")
+		if errC != nil {
+			m := "error deleting deploy package after upload"
+			logger.Error(m, zap.Error(errC))
+		}
+	}()
+
 	if req.ArchivePackage {
 		err = fetcher.archive(srcFilepath, dstFilepath)
 		if err != nil {
@@ -584,6 +592,7 @@ func (fetcher *Fetcher) UploadHandler(w http.ResponseWriter, r *http.Request) {
 		logger.Error(e, zap.Error(err))
 		http.Error(w, fmt.Sprintf("%s: %v", e, err), http.StatusInternalServerError)
 	}
+
 }
 
 func (fetcher *Fetcher) rename(src string, dst string) error {