[fieldImages] Move Java fields to edu.wpi.first.fields (#6694)

Doesn't make sense in edu.wpi.fields, and resources are already in
edu.wpi.first.fields
This will require changes in Shuffleboard and Pathweaver

fieldImages/src/main/java/edu/wpi/first/fields/FieldConfig.java

@@ -0,0 +1,88 @@
+// 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.first.fields;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.URL;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+public class FieldConfig {
+  public static class Corners {
+    @JsonProperty("top-left")
+    public double[] m_topLeft;
+
+    @JsonProperty("bottom-right")
+    public double[] m_bottomRight;
+  }
+
+  @JsonProperty("game")
+  public String m_game;
+
+  @JsonProperty("field-image")
+  public String m_fieldImage;
+
+  @JsonProperty("field-corners")
+  public Corners m_fieldCorners;
+
+  @JsonProperty("field-size")
+  public double[] m_fieldSize;
+
+  @JsonProperty("field-unit")
+  public String m_fieldUnit;
+
+  public FieldConfig() {}
+
+  public URL getImageUrl() {
+    return getClass().getResource(Fields.kBaseResourceDir + m_fieldImage);
+  }
+
+  public InputStream getImageAsStream() {
+    return getClass().getResourceAsStream(Fields.kBaseResourceDir + m_fieldImage);
+  }
+
+  /**
+   * Loads a predefined field configuration from a resource file.
+   *
+   * @param field The predefined field
+   * @return The field configuration
+   * @throws IOException Throws if the file could not be loaded
+   */
+  public static FieldConfig loadField(Fields field) throws IOException {
+    return loadFromResource(field.m_resourceFile);
+  }
+
+  /**
+   * Loads a field configuration from a file on disk.
+   *
+   * @param file The json file to load
+   * @return The field configuration
+   * @throws IOException Throws if the file could not be loaded
+   */
+  public static FieldConfig loadFromFile(Path file) throws IOException {
+    try (BufferedReader reader = Files.newBufferedReader(file)) {
+      return new ObjectMapper().readerFor(FieldConfig.class).readValue(reader);
+    }
+  }
+
+  /**
+   * Loads a field configuration from a resource file located inside the programs jar file.
+   *
+   * @param resourcePath The path to the resource file
+   * @return The field configuration
+   * @throws IOException Throws if the resource could not be loaded
+   */
+  public static FieldConfig loadFromResource(String resourcePath) throws IOException {
+    try (InputStream stream = FieldConfig.class.getResourceAsStream(resourcePath);
+        InputStreamReader reader = new InputStreamReader(stream)) {
+      return new ObjectMapper().readerFor(FieldConfig.class).readValue(reader);
+    }
+  }
+}