[yellowstone] Add yellowstone server for endpoint registration.

sys/yellowstone/yellowstone_server.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <glacier/status/error_or.h>
+#include <mammoth/endpoint_server.h>
+#include <mammoth/port.h>
+#include <mammoth/thread.h>
+
+class YellowstoneServer {
+ public:
+  static glcr::ErrorOr<YellowstoneServer> Create();
+
+  Thread RunServer();
+  Thread RunRegistration();
+
+  void ServerThread();
+  void RegistrationThread();
+
+  glcr::ErrorOr<EndpointClient> GetServerClient();
+
+ private:
+  EndpointServer server_;
+  Port register_port_;
+
+  static const uint64_t kBufferSize = 128;
+  uint8_t server_buffer_[kBufferSize];
+  char registration_buffer_[kBufferSize];
+
+  // TODO: Store these in a data structure.
+  z_cap_t denali_cap_ = 0;
+  z_cap_t victoria_falls_cap_ = 0;
+
+  YellowstoneServer(EndpointServer server, Port port);
+};