extract HomeModel from ContentView

huge refactor

Signed-off-by: William Casarin <jb55@jb55.com>

damus/Models/SignalModel.swift

@@ -0,0 +1,32 @@
+//
+//  SignalModel.swift
+//  damus
+//
+//  Created by William Casarin on 2022-05-24.
+//
+
+import Foundation
+
+
+class SignalModel: ObservableObject {
+    @Published var signal: Int
+    @Published var max_signal: Int
+    
+    var percentage: Double {
+        if max_signal == 0 {
+            return 0
+        }
+        
+        return Double(signal) / Double(max_signal)
+    }
+    
+    init() {
+        self.signal = 0
+        self.max_signal = 0
+    }
+    
+    init(signal: Int, max_signal: Int) {
+        self.signal = signal
+        self.max_signal = max_signal
+    }
+}