Most relevant processors/commands

[rtripault]

Add most useful processors as commands and a few "interesting" ones :

• reset a user password (sending her an email to validate the password change)
• disable a plugin (either providing its name/ID)
• install a new Revo instance (with the ability to define a "template" for paths)
• upgrade a Revo instance
• download & install packages from providers
• list packages having upgrades available
• backup a Revo instance (fits into a third party component/library)