New language independent course (#8677)

* New language independent course

* Fix osdev course link

* Update courses/free-courses-pl.md

* Apply suggestions from code review

Co-authored-by: Sharan J <50091666+shrn01@users.noreply.github.com>

courses/free-courses-pl.md

@@ -1,5 +1,6 @@
 ### Index
 
+* [0 - Niezależne od języka programowania](#0---niezale%C5%BCne-od-j%C4%99zyka-programowania)
 * [Assembly Language](#assembly-language)
 * [Bash](#bash)
 * [Brainfuck](#brainfuck)
@@ -16,6 +17,11 @@
 * [Swift](#swift)
 
 
+### 0 - Niezależne od języka programowania
+
+* [OSDev](https://www.youtube.com/playlist?list=PLGhEqiD7wAd5D-fe-Qz027_1yAH3rFMYF) - Gynvael Coldwind
+
+
 ### Assembly Language
 
 * [Gynvael's Asm (PL)](https://www.youtube.com/playlist?list=PL7CA8FE35B665D4DD) - Gynvael Coldwind