Feature: track deprecated status

[knolleary]

We want the ability to track if a module is deprecated. This is a step before being removed from the library - where it's valid to still use the module, but there may be a better alternative available.

We will:

• update a deprecated flag on the module meta data if it has been deprecated on npm
• provide an admin-only way to manually set/clear the deprecated flag with a message.

The module's page will need to show the deprecation warning.

The catalogue.json should be updated to include the deprecated property.

node-red/node-red#5126 covers updated the palette manager to show the info in the editor.