cluster/identd/ident: add basic ident protocol server

This adds an ident protocol server and tests for it.

Change-Id: I830f85faa7dce4220bd7001635b20e88b4a8b417
diff --git a/cluster/identd/ident/BUILD.bazel b/cluster/identd/ident/BUILD.bazel
index b672c92..382900e 100644
--- a/cluster/identd/ident/BUILD.bazel
+++ b/cluster/identd/ident/BUILD.bazel
@@ -6,6 +6,7 @@
         "client.go",
         "request.go",
         "response.go",
+        "server.go",
     ],
     importpath = "code.hackerspace.pl/hscloud/cluster/identd/ident",
     visibility = ["//visibility:public"],
@@ -17,6 +18,7 @@
     srcs = [
         "request_test.go",
         "response_test.go",
+        "server_test.go",
     ],
     embed = [":go_default_library"],
     deps = ["@com_github_go_test_deep//:go_default_library"],