Refactor common IMU code into frc971

This lets us have different main functions for different years to manage
the hardware complexity.

Change-Id: Ia0fbef081265b6301e1d9e9ecc4f1d496f43a9cc
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/frc971/imu_reader/BUILD b/frc971/imu_reader/BUILD
new file mode 100644
index 0000000..7d424c4
--- /dev/null
+++ b/frc971/imu_reader/BUILD
@@ -0,0 +1,21 @@
+cc_library(
+    name = "imu",
+    srcs = [
+        "imu.cc",
+    ],
+    hdrs = [
+        "imu.h",
+    ],
+    target_compatible_with = ["@platforms//os:linux"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//aos/events:epoll",
+        "//aos/events:shm_event_loop",
+        "//aos/util:crc32",
+        "//frc971/wpilib:imu_batch_fbs",
+        "//frc971/wpilib:imu_fbs",
+        "//y2022:constants",
+        "@com_github_google_glog//:glog",
+        "@com_google_absl//absl/types:span",
+    ],
+)