events: move types into service package

When using events, it was found to be fairly unwieldy with a number of
extra packages. For the most part, when interacting with the events
service, we want types of the same version of the service. This has been
accomplished by moving all events types into the events package.

In addition, several fixes to the way events are marshaled have been
included. Specifically, we defer to the protobuf type registration
system to assemble events and type urls, with a little bit sheen on top
of add a containerd.io oriented namespace.

This has resulted in much cleaner event consumption and has removed the
reliance on error prone type urls, in favor of concrete types.

Signed-off-by: Stephen J Day <stephen.day@docker.com>

api/services/events/v1/runtime.proto

@@ -0,0 +1,45 @@
+syntax = "proto3";
+
+package containerd.services.events.v1;
+
+import "gogoproto/gogo.proto";
+import "google/protobuf/timestamp.proto";
+import "github.com/containerd/containerd/api/types/task/task.proto";
+
+option go_package = "github.com/containerd/containerd/api/services/events/v1;events";
+
+message RuntimeIO {
+	string stdin = 1;
+	string stdout = 2;
+	string stderr = 3;
+	bool terminal = 4;
+}
+
+message RuntimeMount {
+	string type = 1;
+	string source = 2;
+	repeated string options = 3;
+}
+
+message RuntimeCreate {
+	string id = 1;
+	string bundle = 2;
+	repeated RuntimeMount rootfs = 3 [(gogoproto.customname) = "RootFS"];
+	RuntimeIO io = 4 [(gogoproto.customname) = "IO"];
+	string checkpoint = 5;
+}
+
+message RuntimeEvent {
+	string id = 1;
+	containerd.v1.types.Event.EventType type = 2;
+	uint32 pid = 3;
+	uint32 exit_status = 4;
+	google.protobuf.Timestamp exited_at = 5 [(gogoproto.stdtime) = true, (gogoproto.nullable) = false];
+}
+
+message RuntimeDelete {
+	string id = 1;
+	string runtime = 2;
+	uint32 exit_status = 3;
+	google.protobuf.Timestamp exited_at = 4 [(gogoproto.stdtime) = true, (gogoproto.nullable) = false];
+}