Feature: Replace Processing Dots with Progress Bar

[JC-comp]

This PR aims to implement a new feature by replacing the processing dot mechanism with a progress bar.

Benefits:

• Providing clear feedback to users about the syncing progress
• Eliminating the disruptive output in verbose mode
• Can be further extended to the single file download/upload progress
• Can be further expanded to generate sync reports at the end of each sync cycle, interactive socket communication for GUI tools, etc.

Changes

• Add a progress manager to handle all running progress
• Apply the new progressbar for various tasks: database scan, filesystem scan, fetching delta, new local file upload, changed local file upload, and downloading.

Effect