feat(junie): added .devcontainer.json

Author: jetbrains-junie[bot]

.devcontainer/devcontainer.json

@@ -0,0 +1,12 @@
+{
+  "name": "Java",
+  "image": "mcr.microsoft.com/devcontainers/java:1-21",
+  "features": {
+    "ghcr.io/devcontainers/features/java:1": {
+      "version": "none",
+      "installMaven": "true",
+      "mavenVersion": "3.8.6",
+      "installGradle": "true"
+    }
+  }
+}