Support a basic client-side login flow

I will need to remove some of the baggage like:

- Scrub any copy about restaurants
- delete Restaurant.elm
- Change Owner.elm -> Manager.elm

client/src/Utils.elm

@@ -0,0 +1,90 @@
+module Utils exposing (..)
+
+import DateFormat
+import Http
+import Time
+import Shared
+
+
+explainHttpError : Http.Error -> String
+explainHttpError e =
+    case e of
+        Http.BadUrl _ ->
+            "Bad URL: you may have supplied an improperly formatted URL"
+
+        Http.Timeout ->
+            "Timeout: the resource you requested did not arrive within the interval of time that you claimed it should"
+
+        Http.BadStatus s ->
+            "Bad Status: the server returned a bad status code: " ++ String.fromInt s
+
+        Http.BadBody b ->
+            "Bad Body: our application had trouble decoding the body of the response from the server: " ++ b
+
+        Http.NetworkError ->
+            "Network Error: something went awry in the network stack. I recommend checking the server logs if you can."
+
+
+getWithCredentials :
+    { url : String
+    , expect : Http.Expect msg
+    }
+    -> Cmd msg
+getWithCredentials { url, expect } =
+    Http.riskyRequest
+        { url = url
+        , headers = [ Http.header "Origin" Shared.clientOrigin ]
+        , method = "GET"
+        , timeout = Nothing
+        , tracker = Nothing
+        , body = Http.emptyBody
+        , expect = expect
+        }
+
+
+postWithCredentials :
+    { url : String
+    , body : Http.Body
+    , expect : Http.Expect msg
+    }
+    -> Cmd msg
+postWithCredentials { url, body, expect } =
+    Http.riskyRequest
+        { url = url
+        , headers = [ Http.header "Origin" Shared.clientOrigin ]
+        , method = "POST"
+        , timeout = Nothing
+        , tracker = Nothing
+        , body = body
+        , expect = expect
+        }
+
+
+deleteWithCredentials :
+    { url : String
+    , expect : Http.Expect msg
+    }
+    -> Cmd msg
+deleteWithCredentials { url, expect } =
+    Http.riskyRequest
+        { url = url
+        , headers = [ Http.header "Origin" Shared.clientOrigin ]
+        , method = "DELETE"
+        , timeout = Nothing
+        , tracker = Nothing
+        , body = Http.emptyBody
+        , expect = expect
+        }
+
+
+formatTime : Time.Posix -> String
+formatTime ts =
+    DateFormat.format
+        [ DateFormat.monthNameFull
+        , DateFormat.text " "
+        , DateFormat.dayOfMonthSuffix
+        , DateFormat.text ", "
+        , DateFormat.yearNumber
+        ]
+        Time.utc
+        ts