Added paradox for list-packages alternative with perspectives support

I am having trouble making these layers lightweight though... they add 0.3 seconds to startup, any tips on how to use `use-package` ?
From what I can tell you could replace this with a `:config` block containing the config stuff in this function. The config block will be automagically run when the package is loaded (i.e when you call `paradox-list-packages` the first time).