Profile certificates

Includes:

• profile certificate generation and server sign.
• storing the profile certificates in the local crypto storage.
• one-time profile certificate generation.

cpp/src/vereign/core/time.cc

+#include <vereign/core/time.hh>
+
+namespace vereign::time {
+
+auto Epoch() -> boost::posix_time::ptime {
+  static const auto epoch = boost::posix_time::ptime{boost::gregorian::date{1970, 1, 1}};
+
+  return epoch;
+}
+
+auto PosixTimeToTime(boost::posix_time::ptime t) -> time_t {
+  return time_t((t - Epoch()).total_seconds());
+}
+
+auto MakePosixTime(
+  int year,
+  int month,
+  int day,
+  int hours,
+  int minutes,
+  int seconds
+) -> boost::posix_time::ptime {
+  using namespace boost::posix_time;
+  using namespace boost::gregorian;
+
+  return ptime(
+    date{
+      static_cast<date::year_type>(year),
+      static_cast<date::month_type>(month),
+      static_cast<date::day_type>(day)
+    },
+    time_duration(hours, minutes, seconds)
+  );
+}
+
+auto MakeTimeUTC(
+  int year,
+  int month,
+  int day,
+  int hours,
+  int seconds,
+  int milliseconds
+) -> time_t {
+  using namespace boost::posix_time;
+  using namespace boost::gregorian;
+
+  return PosixTimeToTime(
+    ptime(
+      date{
+        static_cast<date::year_type>(year),
+        static_cast<date::month_type>(month),
+        static_cast<date::day_type>(day)
+      },
+      time_duration(hours, seconds, milliseconds)
+    )
+  );
+}
+
+auto MakeTimeUTCFromString(const std::string& str) -> time_t {
+  using namespace boost::posix_time;
+  using namespace boost::gregorian;
+
+  return PosixTimeToTime(boost::posix_time::time_from_string(str));
+}
+
+auto MakeTimeUTCFromISO(const std::string& str) -> time_t {
+  using namespace boost::posix_time;
+  using namespace boost::gregorian;
+
+  return PosixTimeToTime(from_iso_string(str));
+}
+
+} // vereign::time