core/api: move to core/proto

This is keeping in line with conventions that protobuf files generally
live in a 'proto/' directory. Even without that, a lot of the protos in
there aren't actually part of an API, so keeping them in `api/` is a bit
of a misnomer.

We also remove unused protos that were part of the old
integrity/lifecycle flow. Again, these will make a comeback.

Test Plan: this should fail. part of a larger stack. D590 is the first tip of the stack that should work.

X-Origin-Diff: phab/D588
GitOrigin-RevId: 4a7af494810348f6bcabd49e63902b4c47e6ec35
diff --git a/core/proto/internal/BUILD.bazel b/core/proto/internal/BUILD.bazel
new file mode 100644
index 0000000..aa16e97
--- /dev/null
+++ b/core/proto/internal/BUILD.bazel
@@ -0,0 +1,23 @@
+load("@rules_proto//proto:defs.bzl", "proto_library")
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+load("@io_bazel_rules_go//proto:def.bzl", "go_proto_library")
+
+proto_library(
+    name = "internal_proto",
+    srcs = ["internal.proto"],
+    visibility = ["//core:__subpackages__"],
+)
+
+go_proto_library(
+    name = "internal_go_proto",
+    importpath = "git.monogon.dev/source/nexantic.git/core/proto/internal",
+    proto = ":internal_proto",
+    visibility = ["//core:__subpackages__"],
+)
+
+go_library(
+    name = "go_default_library",
+    embed = [":internal_go_proto"],
+    importpath = "git.monogon.dev/source/nexantic.git/core/proto/internal",
+    visibility = ["//core:__subpackages__"],
+)