Provide the complete String "module" which provides all the features of elm/core

[DamianReeves]

Provide all the functionality that is available in elm/core's String module:
https://package.elm-lang.org/packages/elm/core/1.0.5/String

• We are targeting compatibility with version 1.0.5 of elm/core
• We should provide a fairly performant implementation
• Regards should be made for how Elm (and as such the morphir SDK) has a proclivity for currying and partial application.