Add C++ PNG/JPEG converter for foxglove CompressedImage

This gives us a converter that we can slot into C++ code to convert our
CameraImage type into foxglove CompressedImage types, for more efficient
display.

Change-Id: I6e831c341ca90ca26b38af504c1bb86d482cf561
Signed-off-by: James Kuszmaul <jabukuszmaul@gmail.com>
diff --git a/frc971/vision/BUILD b/frc971/vision/BUILD
index 094021d..c52afae 100644
--- a/frc971/vision/BUILD
+++ b/frc971/vision/BUILD
@@ -251,3 +251,16 @@
         "@com_google_absl//absl/strings",
     ],
 )
+
+cc_library(
+    name = "foxglove_image_converter",
+    srcs = ["foxglove_image_converter.cc"],
+    hdrs = ["foxglove_image_converter.h"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":vision_fbs",
+        "//aos/events:event_loop",
+        "//third_party:opencv",
+        "@com_github_foxglove_schemas//:schemas",
+    ],
+)