Update `Supporting Tools and Services` to include the latest MCP customization features

As per version `0.80.0` of the devcontainer CLI, MCPs are part of the spec and can be defined by adding a `customization` option in the `.devcontainer.json` file. This information is made available in the [VS Code website](https://code.visualstudio.com/updates/v1_102#_dev-container-support-for-mcp-configuration). It would be useful to have this made available in containers.dev, more specifically in the `Supporting Tools and Services` page, where other such settings are mentioned.