feat: add files permissions & automatic update shared files

[lucas-louis]

[FEATURES] [Add files permissions & automatic update shared files]

Description

• Add file permissions (read, write)
• Add the possibility to edit a file for every contacts who have the permission to see this file

Describe the solution you'd like

When a contact updates a shared file, all the contacts linked to this file can access to the new version of the file uploaded by the editor. Only the contacts with the 'writing' permission can update the files.

Additional context

• ⚠️ This issue is linked to the feat: add the possibility to edit files into IPC #28

[RezaRahemtola]

When a contact updates a shared file, all the contacts linked to this file can access to the new version of the file uploaded by the editor.

This part is implemented in #61.