[#74] apemanager: Generate protobufs for apemanager service

* Generate protobufs.
* Make marshallers, unmarshallers, json-encoders etc.
* Create message encoding/decoding unit-tests.

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

apemanager/grpc/types.go

@@ -0,0 +1,21 @@
+package apemanager
+
+func (t *ChainTarget) SetType(typ TargetType) {
+	t.Type = typ
+}
+
+func (t *ChainTarget) SetName(name string) {
+	t.Name = name
+}
+
+func (c *Chain) SetKind(kind isChain_Kind) {
+	c.Kind = kind
+}
+
+func (cr *Chain_Raw) SetRaw(raw []byte) {
+	cr.Raw = raw
+}
+
+func (cr *Chain_Raw) GetRaw() []byte {
+	return cr.Raw
+}