Initial implementation of procfile

Reviewed-on: #1

Pushy.Domain/ITextItem.cs

@@ -0,0 +1,14 @@
+using Orleans.Concurrency;
+
+namespace Pushy.Domain;
+
+public interface ITextItem : IGrainWithStringKey
+{
+    [Alias("SetText")]
+    public ValueTask<TextSetResult> SetText(string text);
+    
+    [ReadOnly]
+    [return: Immutable]
+    [Alias("GetText")]
+    ValueTask<string> GetText();
+}