Added gitignore for TP 4

TP4/.gitignore

+.gradle
+build/
+!gradle/wrapper/gradle-wrapper.jar
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### IntelliJ IDEA ###
+.idea/
+
+### VS Code ###
+.vscode/
+
+### Mac OS ###
+.DS_Store
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