**Reasons for making this change:**

Workspace file can allow you to have an individual VS Code setting file for each project, which is useful for monorepo-based development.

You can find an example on [lit/lit/lit-next.code-workspace](08f60328ab/lit-next.code-workspace).

**Links to documentation supporting these rule changes:**

https://code.visualstudio.com/docs/editor/multi-root-workspaces#_workspace-file

This will add support for the default location the Local History extension for Visual Studio Code uses.
See https://marketplace.visualstudio.com/items?itemName=xyz.local-history

Added ignore for workspace files (*.code-workspace). They can be added in any directory, depending on the user's preferences.

Added extensions.json as exception in .vscode folder. File is used as
extensions recommendation for project.

Visual Studio Code has a few files that can be placed into the workspace
in order to share settings across users.  Settings.json is for project
specific overrides.  Tasks.json is for executable tasks (build, gulp, etc.)
While launch.json is for debugging specific tasks.

Starting with 0.8.0, VS Code will store its settings in a .vscode folder and no longer in the generic .settings folder.