[tutorial] Add pow tutorial

[sabderemane]

Description of the tutorial
add pow function tutorial

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[HenokB]

Hey, I can work on this one.

[sabderemane]

Done ! The review will be done as soon as possible ☺️

[JatinGera27aug]

hey! if someone else is working on this, I would be happy to do a tutorial on other functions or modules such as Tkinter

[funbeedev]

@JatinGera-noob See issue #133 on the Tkinter module. You may work on that if you wish!

[JatinGera27aug]

Ohk will look at it after returning from college ✌