Add rewind feature

[Arkweid]

Description: Sometimes we need to start read file from beginning.

Definition of Done:

• Module could start read file from beginning
• Add "Read from beginning" button in module UI

[souryogurt]

I'll take it! It seems the current position for each file is stored in the store folder created by the module. I should reset it on the agent's side and restart the watcher thread when the user clicks the "Read from Start" button.
I'll add a new button.