[fieldImages] Add utilities to simplify loading of fields (#4456)

fieldImages/src/main/java/edu/wpi/fields/Fields.java

@@ -0,0 +1,29 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+package edu.wpi.fields;
+
+public enum Fields {
+  k2018PowerUp("2018-powerup.json"),
+  k2019DeepSpace("2019-deepspace.json"),
+  k2020InfiniteRecharge("2020-infiniterecharge.json"),
+  k2021InfiniteRecharge("2021-infiniterecharge.json"),
+  k2021Barrel("2021-barrelracingpath.json"),
+  k2021Bounce("2021-bouncepath.json"),
+  k2021GalacticSearchA("2021-galacticsearcha.json"),
+  k2021GalacticSearchB("2021-galacticsearchb.json"),
+  k2021Slalom("2021-slalompath.json"),
+  k2022RapidReact("2022-rapidreact.json");
+
+  public static final String kBaseResourceDir = "/edu/wpi/first/fields/";
+
+  /** Alias to the current game. */
+  public static final Fields kDefaultField = k2022RapidReact;
+
+  public final String m_resourceFile;
+
+  Fields(String resourceFile) {
+    m_resourceFile = kBaseResourceDir + resourceFile;
+  }
+}