[Breaking change] [Install.Import] Allow adding multiple import statements

[mateusfpleite]

• Changes Install.Import.init to receive a list of records of the type { moduleToImport : String, alias_ : Maybe String, exposedValues ​​: List String }.
• Small tweak to checking to ensure duplicate imports won't prevent other imports from being installed.
• Adjust documentation to reflect new API
• Adjust previous tests to changes and create new tests

Closes #24.

[mateusfpleite]

@jxxcarlson I ended up making the changes to the init function itself instead of adding a new function to keep the module simple and maintain internal consistency, but I'm not sure if this made it less intuitive to use. What do you think?

[jxxcarlson]

Matteus, the new API is really nice. I added another option in the same style:

Install.Import.initSimple "Frontend" [ "Foo.Bar", "Baz.Qux" ]
        |> Install.Import.makeRule