Add a Propulsion.Tool with initAux and/or project facilities formerly managed by eqx tool

[bartelink]

Equinox.Tool presently provides an initAux facility which correctly initializes a ChangeFeedProcessor 'aux' collection correctly. The need for such a tool is not Equinox specific, and should instead be considered a generic need associated with the CFP and/or Propulsion.Cosmos and/or Propulsion.Cosmos2 package in general.

The solution is thus to move Propulsion-related aspects of the tool into a Propulsion.Tool. It may also be useful to reinstate the former eqx project facilities (projecting from Cosmos to either generate stats or feed to kafka) here too (see jet/equinox#138)

• add a tool
• add initAux init
• add project ... stats
• add project ... kafka
• move docs from Equinox's README.md and DOCUMENTATION.md
• target Equinox 2.0.0-rc2