Added developer specification for fuel-plugin-midonet
Added developer specification for fuel-plugin-midonet

Add a new directory called 'specs' in the main tree, which includes the
rst file with the developer specification for the fuel-plugin-midonet

Change-Id: I20c043c350b1f8c8f7b029f772ba4bfed9f791e5

stackforge/fuel-plugin-midonet,stackforge/fuel-plugin-midonet