Add Italian video course about Spring Boot (#5191)

* Add Italian video course about Spring Boot

* Move "Esercitazioni di Spring Boot" under Java category

free-courses-it.md

@@ -110,6 +110,7 @@
 
 ### Java
 
+* [Esercitazioni di Spring Boot](https://www.youtube.com/playlist?list=PLCbSCJEIR6CpGchit9OCI6fX_qVYs78d_) (M. Cicolella)
 * [Java EE](https://www.youtube.com/playlist?list=PLjGYWJ4Dcy-erfReHXB9Ush0cREGSmyIe) (S. Zorba)
 * [Programmazione a Oggetti (Java)](https://www.youtube.com/playlist?list=PLUFFnpJdi99kewGZIHpCDgarZER_-J1am) (M. Torchiano)