Add ability to log

[chshersh]

Since all the work is done behind the scenes and only TUI is shown, it can be really hard to know what's going on. This issue proposes to add support for optional logging. It can be useful for debugging issues.

Specifically,

1. Add a CLI flag for an optional path to logs
2. Add logger to the project to output data in the specified file (only when the file is given)
3. Add log lines

At this point, I can see the following relevant log lines:

• Cloning repo
• Reading file contents
• Every time bat is called
• Received events

This should be a good start.