Code refactoring

[gozeloglu]

Code refactoring is needed for each file.

• https://github.com/gozeloglu/bm/blob/main/bm
• https://github.com/gozeloglu/bm/blob/main/commands/add.sh
• https://github.com/gozeloglu/bm/blob/main/commands/delete.sh
• https://github.com/gozeloglu/bm/blob/main/commands/list.sh
• https://github.com/gozeloglu/bm/blob/main/commands/remove.sh
• https://github.com/gozeloglu/bm/blob/main/commands/setup.sh