Add an explicit way of specifying dependencies on the command line

e.g.,

--dependency="MyOtherLib=MyOtherLib-1.0-073259a42bbf95f818c899c57ba5bf30"

If the package names do not match

--dependency="foo=MyOtherLib-1.0-073259a42bbf95f818c899c57ba5bf30"

then this gives an error

Setup.hs: The following names do match their hash name:
(foo, MyOtherLib)

If the hash is incorrect e.g.

--dependency="foo=MyOtherLib-1.0-073259a42bbf95f818c899c57ba5bf31"

then this gives an error

Setup.hs: The following dependencies do not exist:
MyOtherLib-1.0-073259a42bbf95f818c899c57ba5bf31