Adds card and binder export and import.

Android/app/src/main/java/com/majinnaibu/monstercards/models/BinderExport.java

@@ -0,0 +1,30 @@
+package com.majinnaibu.monstercards.models;
+
+import com.google.gson.annotations.SerializedName;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class BinderExport {
+    @SerializedName("schemaVersion")
+    public int schemaVersion = 1;
+
+    @SerializedName("collections")
+    public List<CollectionExport> collections = new ArrayList<>();
+
+    public static class CollectionExport {
+        @SerializedName("name")
+        public String name;
+
+        @SerializedName("cards")
+        public List<Monster> cards = new ArrayList<>();
+
+        public CollectionExport() {
+        }
+
+        public CollectionExport(String name, List<Monster> cards) {
+            this.name = name != null ? name : "";
+            this.cards = cards != null ? cards : new ArrayList<>();
+        }
+    }
+}

Android/app/src/main/java/com/majinnaibu/monstercards/models/Monster.java

@@ -6,6 +6,7 @@ import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.room.ColumnInfo;
 import androidx.room.Entity;
+import androidx.room.Ignore;
 import androidx.room.PrimaryKey;
 
 import com.majinnaibu.monstercards.data.enums.AbilityScore;
@@ -29,6 +30,9 @@ import java.util.UUID;
 @SuppressWarnings("unused")
 public class Monster {
 
+    @Ignore
+    public int schemaVersion = 1;
+
     @PrimaryKey
     @NonNull
     public UUID id;