[#54] apemanager: Move APE specific types to separate package

* Introduce `ape` package and move `apemanager/types.proto`
  to `ape/`;
* Fix `apemanager/service.proto`.

Signed-off-by: Airat Arifullin <aarifullin@yadro.com>

ape/types.proto

@@ -0,0 +1,33 @@
+syntax = "proto3";
+
+package frostfs.v2.ape;
+
+option go_package = "git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/ape/grpc;ape";
+
+// TargetType is a type target to which a rule chain is defined.
+enum TargetType {
+  UNDEFINED = 0;
+
+  NAMESPACE = 1;
+
+  CONTAINER = 2;
+
+  USER = 3;
+
+  GROUP = 4;
+}
+
+// ChainTarget is an object to which a rule chain is defined.
+message ChainTarget {
+  TargetType type = 1;
+
+  string name = 2;
+}
+
+// Chain is a chain of rules defined for a specific target.
+message Chain {
+  oneof kind {
+    // Raw representation of a serizalized rule chain.
+    bytes raw = 1;
+  }
+}