Added 3 new commands to the cli

• mv and grep: its preatty self explanatory what it does if you ever used linux or any other unix like operating system for that matter
• man: this was kinda hard at first finding where you can find online versions of the manpages from linux that the os can easily get over an api but after a bit of searching i found the tldr pages project and uses that and the github api to download the pages and then strip out the markdown syntax from them and displays them in the terminal.