XD-685 Add Plugin beforeShutdown callback

Allow Plugins to perform module cleanup using
Spring beans from the Module's context

XD-685 Support tap namespace in named channels

XD-685 Add bridge cleanup methods to ChannelRegistrySupport

XD-685 Add create/delete pub/sub channels to ChannelRegistry, disable tap method

XD-685 Create tap pub/sub channels on stream creation

- Create channel "tap:streamname.modulename" for each
module in a new stream, tapping into the module's output
channel. These tap channels can later
be used as named channels in other stream definitions.

- Supported syntax for tapping is now "stream create
mytap --definition ":tap:streamname > sink" or
":tap:streamname.module > sink". "tap:streamname"
will not work on a stream where source module is
a named channel (for now)

- Temporarily disallows tapping of named channels,
labels, or streams whose source is a named channel

XD-685 Remove support for tap commands

XD-685 Bind Rabbit FanoutExchange on inbound pub/sub