Add "Raspberry Pi basics course" from forbot.pl (#6257)

* Add "Raspberry Pi basics course" from forbot.pl

* fix order

* Update books/free-programming-books-pl.md
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>

* Review changes
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>

courses/free-courses-pl.md

@@ -104,6 +104,7 @@
 * [Kurs Python - Darmowy Po Polsku](https://www.youtube.com/playlist?list=PL_dDQ_G9rdI6dQsDkwqSQyAeXY3uUrWzp)
 * [Kurs Python 3](https://www.youtube.com/playlist?list=PLdBHMlEKo8UcOaykMssI1_X6ui0tzTNoH)
 * [Python 3 - Kurs wideo](https://www.youtube.com/playlist?list=PLbOPmSDkHx2pCboufcEKkinpUuramshmr)
+* [Raspberry Pi kurs od podstaw](https://forbot.pl/blog/kurs-raspberry-pi-od-podstaw-wstep-spis-tresci-id23139) - Piotr Bugalski (FORBOT.pl)
 
 
 ### Swift