Add app into cache's key

[k82cn]

Motivation

Currently, the objects are stored by session; but the flamepy.runner need to store object cross sessions. This feature is used to enhance object_cache for flamepy.runner.

Function Specification

1. Enhance flamepy.runner to have put_object: rr.put_object which will use <app_name>/shared as key prefix for object
2. The object endpoint will be updated to //
3. The shared/default are reserved session name for object

Solutions

The object will be stored as //.arrow by flame-object-cache. Backward compatibility is not required.

Additional context

N/A

[k82cn]

fixed by #425