Add devcontainer support (halo-dev#6252)

#### What type of PR is this?

/kind improvement
/area core

#### What this PR does / why we need it:

This PR adds  devcontainer support for a better development experience.

#### Does this PR introduce a user-facing change?

```release-note
None
```

.devcontainer/devcontainer.json

@@ -0,0 +1,49 @@
+// For format details, see https://aka.ms/devcontainer.json. For config options, see the
+// README at: https://github.com/devcontainers/templates/tree/main/src/docker-in-docker
+{
+    "name": "Halo Dev Container",
+    // Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
+    "image": "mcr.microsoft.com/devcontainers/base:bullseye",
+
+    "features": {
+        "ghcr.io/devcontainers/features/docker-in-docker:2": {
+            "version": "20.10",
+            "enableNonRootDocker": "true",
+            "moby": "true"
+        },
+        "ghcr.io/devcontainers/features/java:1": {
+            "version": "17",
+            "jdkDistro": "tem"
+        },
+        "ghcr.io/devcontainers/features/node:1": {
+            "version": "20"
+        },
+        "ghcr.io/devcontainers/features/github-cli:1": {}
+    },
+    "customizations": {
+        "vscode": {
+            "extensions": [
+                "Vue.volar",
+                "vscodevim.vim",
+                "shengchen.vscode-checkstyle",
+                "streetsidesoftware.code-spell-checker",
+                "vscjava.vscode-gradle",
+                "vmware.vscode-boot-dev-pack",
+                "vscjava.vscode-java-pack",
+                "bradlc.vscode-tailwindcss"
+            ]
+        }
+    }
+
+    // Use 'forwardPorts' to make a list of ports inside the container available locally.
+    // "forwardPorts": [],
+
+    // Use 'postCreateCommand' to run commands after the container is created.
+    // "postCreateCommand": "docker --version",
+
+    // Configure tool-specific properties.
+    // "customizations": {},
+
+    // Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root.
+    // "remoteUser": "root"
+}

.github/dependabot.yml

@@ -0,0 +1,12 @@
+# To get started with Dependabot version updates, you'll need to specify which
+# package ecosystems to update and where the package manifests are located.
+# Please see the documentation for more information:
+# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+# https://containers.dev/guide/dependabot
+
+version: 2
+updates:
+    - package-ecosystem: "devcontainers"
+      directory: "/"
+      schedule:
+          interval: weekly