ydb initial

https://github.com/chrislusf/seaweedfs/issues/2942

weed/filer/ydb/readme.md

@@ -0,0 +1,27 @@
+## YDB
+
+database: https://github.com/ydb-platform/ydb
+go driver: https://github.com/ydb-platform/ydb-go-sdk
+
+options:
+
+```
+[ydb]
+enabled=true
+db_name="seaweedfs"
+servers=["http://localhost:8529"]
+#basic auth
+user="root"
+pass="test"
+
+# tls settings
+insecure_skip_verify=true
+```
+
+get ydb types
+```
+ydbgen -dir weed/filer/ydb
+```
+
+i test using this dev database:
+`make dev_ydb`