docs: Removed and purged uneeded docs. (#2273)

docs/backend/fs/README.md

@@ -0,0 +1,25 @@
+### Backend format `fs.json`
+
+```go
+// objectPartInfo Info of each part kept in the multipart metadata
+// file after CompleteMultipartUpload() is called.
+type objectPartInfo struct {
+	Number int    `json:"number"`
+	Name   string `json:"name"`
+	ETag   string `json:"etag"`
+	Size   int64  `json:"size"`
+}
+
+// A fsMetaV1 represents a metadata header mapping keys to sets of values.
+type fsMetaV1 struct {
+	Version string `json:"version"`
+	Format  string `json:"format"`
+	Minio   struct {
+		Release string `json:"release"`
+	} `json:"minio"`
+	// Metadata map for current object `fs.json`.
+	Meta  map[string]string `json:"meta,omitempty"`
+	Parts []objectPartInfo  `json:"parts,omitempty"`
+}
+
+```

docs/backend/fs/fs.json

@@ -4,6 +4,10 @@
     "minio": {
         "release": "DEVELOPMENT.GOGET"
     },
+    "meta": {
+        "content-type": "binary/octet-stream",
+        "content-encoding": "gzip"
+    },
     "parts": [
         {
             "number": 1,