feat(workspaces): introduce new workspaces root selector

[darcyclarke]

Summary

• Introduce new --include-workspace-root config
• --workspaces becomes a trinary (ie. defaults to null)

Default:
  Command is ran under the context of the root project only
  Workspaces are used in node_modules if the name matches the required dependency

--workspaces
  Command is ran under the context of every workspace
  Command is not ran under the context fo the root project
  Workspaces are used in node_modules if the name matches the required dependency

--workspace x
  Command is ran under the context of workspace x
  Command is not ran under the context fo the root project
  Workspaces are used in node_modules if the name matches the required dependency


--workspace x --include-workspace-root
  Command is ran under the context of workspace x
  Command is also ran under the context of the root project
  Workspaces are used in node_modules if the name matches the required dependency


--no-workspaces
  Command is ran under the context of the root project only
  Workspaces are not used in node_modules

--no-workspaces --include-workspace-root
  Redundant

--no-workspaces --workspace x
  Throws an exception

[darcyclarke]

Landed support in v8.1.0 - https://github.com/npm/cli/releases/tag/v8.1.0