Begin working on Habit Screens project

Created a small MVP for digitizing my weekly habits. Much more to come.

Lots of things happening:

- Copied the boilerplate to get started
- Added a brief project-level README
- Outlined my ambitions in design.md

See README and design.md for more context on this project.

scratch/habit-screens/client/src/Main.elm

@@ -0,0 +1,27 @@
+module Main exposing (main)
+
+import Browser
+import Habits
+import Html exposing (..)
+import State
+
+
+subscriptions : State.Model -> Sub State.Msg
+subscriptions model =
+    Sub.none
+
+
+view : State.Model -> Html State.Msg
+view model =
+    case model.view of
+        State.Habits ->
+            Habits.render model
+
+
+main =
+    Browser.element
+        { init = \() -> State.init
+        , subscriptions = subscriptions
+        , update = State.update
+        , view = view
+        }