Update use-package configurations

[zoliky]

:bind defers the loading of the package (see https://github.com/jwiegley/use-package#modes-and-interpreters) preventing load-theme to load the theme (even if load-theme is before :bind). I updated the code to use :init instead.

:ensure nil tells Emacs to configure the built-in package and do not look for it in the online repositories.

Also, I use :custom instead of :config because C-h v categorizes all those variables in the "customization" category.

As far as I know only those that do not have "Customize" listed should be added to :config. At least, that's what I do in all my configs.

Variables listed in the :custom don't require setq.

I tested the configurations.