Add a section on Upgrading Packages

[phreed]

The Zero Touch Installer is fine for new installations.
Upgrading existing installations is also important.
Add an Upgrade section which describes how to upgrade each element individually.
This can probably be accomplished by improving the Manual installation section.

Services

• upgrade NodeRed
• upgrade FTS
• upgrade FTS-UI
• upgrade Video Server
• upgrade Chat Server
• upgrade WebMap