Add a CLI

This release adds the log command which enables the following;

• To log doses directly from the CLI without entering the TUI
• To enter the log screen directly, bypassing the start menu

This release also alters the manner in which a path can be provided.
From now on this takes place using the -f flag.

Lastly, the release adds a -h flag to show help in the terminal.

For more information, refer to README.md.