[Enhancement] Allow Python: <class 'module'> as argument to pyimport

[jlapeyre]

With these methods:

pyimport((m, k)::Pair{Py}) = pyimport(string(m.__name__) => k)
pyimport((m, ks)::Pair{Py,<:Tuple}) = pyimport(string(m.__name__) => ks)

you can do something like

amodule = pyimport("amodule")
afunc = pyimport(amodule.submodule1.submodule2, "afunc")

You can use TAB completion at the REPL to get the submodules. This is more convenient than finding and typing the strings.

I don't know how robust string(m.__name__) is.