Move camera.h to the frc971/ folder

The code for dealing with camera transformations is reasonably
year-generic, so move it into frc971/.

Change-Id: I7751ccd01c3e45093c8e548d65e0087b615f0ae0
diff --git a/y2019/control_loops/drivetrain/BUILD b/y2019/control_loops/drivetrain/BUILD
index bc76d7a..aabd3e5 100644
--- a/y2019/control_loops/drivetrain/BUILD
+++ b/y2019/control_loops/drivetrain/BUILD
@@ -100,30 +100,11 @@
 )
 
 cc_library(
-    name = "camera",
-    srcs = ["camera.h"],
-    visibility = ["//y2019:__pkg__"],
-    deps = [
-        "//aos/containers:sized_array",
-        "//frc971/control_loops:pose",
-    ],
-)
-
-cc_test(
-    name = "camera_test",
-    srcs = ["camera_test.cc"],
-    deps = [
-        ":camera",
-        "//aos/testing:googletest",
-    ],
-)
-
-cc_library(
     name = "localizer",
     hdrs = ["localizer.h"],
     deps = [
-        ":camera",
         "//frc971/control_loops:pose",
+        "//frc971/control_loops/drivetrain:camera",
         "//frc971/control_loops/drivetrain:hybrid_ekf",
     ],
 )
@@ -133,9 +114,9 @@
     srcs = ["target_selector.cc"],
     hdrs = ["target_selector.h"],
     deps = [
-        ":camera",
         ":target_selector_fbs",
         "//frc971/control_loops:pose",
+        "//frc971/control_loops/drivetrain:camera",
         "//frc971/control_loops/drivetrain:localizer",
         "//y2019:constants",
         "//y2019/control_loops/superstructure:superstructure_goal_fbs",