Fix crash decoding statuses sent from certain applications

If an application provides its URL as an empty string, decoding it would
cause throw an error because Foundation's URL class does not accept
empty strings. Instead, during parsing, consume the invalid URL and
replace it with a `nil` app URL.

Pachyderm/Model/Application.swift

@@ -12,6 +12,19 @@ public class Application: Decodable {
     public let name: String
     public let website: URL?
     
+    public required init(from decoder: Decoder) throws {
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+        
+        self.name = try container.decode(String.self, forKey: .name)
+        
+        if let websiteStr = try container.decodeIfPresent(String.self, forKey: .website),
+            let url = URL(string: websiteStr) {
+            self.website = url
+        } else {
+            self.website = nil
+        }
+    }
+    
     private enum CodingKeys: String, CodingKey {
         case name
         case website