Statemine Release Prep (#460)

* set default para id to 1000

* add genesis value generation script

* add statemine chain spec and genesis values

* add westmint chain spec and genesis values

* rename chain specs to _genesis to indicate that they are not usable for syncing the chain

* adjust chain names to reduce confusion

* add westmint chain spec

* set chain id to shell

* comment out statemine chain spec

* fix build

Co-authored-by: joepetrowski <joe@parity.io>