* ros2GH-69 Read storage content in a separate thread

For now the publishing starts only after the reading is completly
done. This should change aufter ros2GH-68 is done and a thread-safe
queue can be used instead of std::queue.

* ros2GH-71 Add integration test for timing behavior

* ros2GH-68 Introduce vendor package for shared queue

- Download and install headers from moodycamel readerwriterqueue
- Download and install headers from moodycamel concurrentqueue
- Use readerwriterqueue in code to load and publish concurrently

* ros2GH-71 Retain time difference of messages when playing a bag file

- The main (play) thread sleeps until the time for publishing the
  message is reached.
- Using std::chrono time_point and duration for type-safe time
  arithmetic instead of rcutils time types.

* ros2GH-71 Improve stability of read test

- Subscribers need to maintain a longer history if the messages are
  not consumed fast enough.

* ros2GH-71 Fix Classloader instance lifetime

The Classloader instance needs to outlive all objects created by it.

* ros2GH-71 Extract playing code into a class of its own

Reason: record and play have almost no common code but do the exact
opposite with the storage and rclcpp.

* ros2GH-70 Do not link explicitly against std_msgs

- only required in tests
- this decreases the amount of packages needed for a clean build without tests

* ros2GH-70 Fix error message of storage

* ros2GH-70 Fix pluginlib/storage issue for recording

* ros2GH-71 Cleanup: variable naming

* ros2GH-70 Load storage continuously instead of as fast as possible

- Only load if queue contains less than 1000 messages
- Wait a millisecond before loading again once the queue is long enough

* ros2GH-70 Add options struct to allow specification of queue size

* ros2GH-72 Wait for messages to fill up

* ros2GH-74 Rename integration tests to play/record tests

* ros2GH-74 Use test_msgs in integration tests

- gets rid of string_msgs dependency

* ros2GH-70 Rename is_not_ready to is_pending, use bulk reading to queue

* ros2GH-70 Harmonize storage_loading_future variable

* ros2GH-88 Read messages in order of their timestamps

- Currently, we write sequentially in order of arrival time so
  reading in id order is fine
- This may change at a later time and should not change the reading
  behaviour, i.e. we need to read in order of timestamps

* Fix compiler error on Mac

* ros2GH-8 Fix: use correct ros message type in test

* ros2GH-8 Cleanup: minor code style fixes

* ros2GH-8 Refactor future usage in player

Make the future a class member of player to avoid having to hand it
into several functions which is difficult with a move-only type.

* ros2GH-8 Cleanup: remove verbose logging for every stored message

* ros2GH-8 Refactor rosbag2 interface

Add an explicit overload for record without a topic_names argument to
record all topics.

* fix: call vector.reserve instead of default initalization

* fix record demo