Use a task file for the beginner apps.

Lets you set the DEFMT_LOG env variable more easily even with VS Code is auto-building the code.

beginner/apps/.vscode/launch.json

@@ -7,9 +7,9 @@
         "executable": "./target/thumbv7em-none-eabihf/debug/hello", 
         "name": "Debug Microcontroller (launch)",
         "request": "launch",
-        "preLaunchTask": "rust: cargo build",
+        "preLaunchTask": "Build Rust (Debug)",
         "type": "cortex-debug",
-        "runToMain": true,
+        "runToEntryPoint": "main",
         "configFiles": [
           "interface/jlink.cfg",
         ],

beginner/apps/.vscode/tasks.json

@@ -0,0 +1,27 @@
+{
+    // See https://go.microsoft.com/fwlink/?LinkId=733558
+    // for the documentation about the tasks.json format
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Build Rust (Debug)",
+            "type": "shell",
+            "command": "cargo build",
+            "options": {
+                "env": {
+                    "DEFMT_LOG": "debug",
+                }
+            }
+        },
+        {
+            "label": "Build Rust (Warn)",
+            "type": "shell",
+            "command": "cargo build",
+            "options": {
+                "env": {
+                    "DEFMT_LOG": "warn",
+                }
+            }
+        }
+    ]
+}