Use Reader's seek() method for seeking/jumping in Player

[lihui815]

Closes #824

The current Player->seek() was implemented before storage and by extension the reader exposed seek interface (#824). This PR updates the implementation to use the Reader's seek() method, which reduces the implementation complexity.

Other details:

• Reader's seek() method does not require closing and reopening. Thus it's preferable to just keep the reader open from the constructor, and close it in the destructor. Other methods can just assume an open reader and set seek() as needed.
• Removed the release_reader() method as the player is basically useless after releasing the reader anyway. This removes one more way the reader can get closed before play ends.
• Player seek() method no longer special cases seeking to a timestamp after the end of the bag. Previously, if no messages are found after the seek time, the Player will reset to the original time stamp before the seek method was called. Now, seek will always be performed, and seeking to a later timestamp will either end bag play or loop according to player options. This makes seek behavior to be consistent with the behavior of playing until the end of the bag. There is also no reason to return true/false depending on the success of seek, as the seek will always be successful.

[emersonknapp]

This implementation is so nice and clean - I love it!

I have one concern related to the edge-case behavior noted in the Player::seek docstring comment

If we seek to a time before the bag, e.g. bag_start minus 1 minute - this implementation sets the clock back there, which means that the full minute will have to elapse in real time before the beginning of the bag starts playing. I am thinking that we should "clamp" the clock->jump calls to the bag_start/end range. What do you think?

[emersonknapp]

Sanity check build just to catch any weird compiler xplatform stuff early

Gist: https://gist.githubusercontent.com/emersonknapp/d58facdff381d74d9fc79f29e4165abc/raw/789a662a1682a36f3a38dcf78ef6dd7b34dc3604/ros2.repos
BUILD args: --packages-up-to rosbag2_transport rosbag2_tests rosbag2
TEST args: --packages-select rosbag2_transport rosbag2_tests rosbag2
ROS Distro: rolling
Job: ci_launcher
ci_launcher ran: https://ci.ros2.org/job/ci_launcher/9083

• Linux
• Linux-aarch64
• macOS
• Windows

[emersonknapp]

Gist: https://gist.githubusercontent.com/emersonknapp/d4c53f3799483d9438a478bdc793b532/raw/2d45f2d76b98e4754577b94965a7e9f31a09ad52/ros2.repos
BUILD args: --packages-up-to rosbag2_transport rosbag2_tests rosbag2
TEST args: --packages-select rosbag2_transport rosbag2_tests rosbag2
ROS Distro: rolling
Job: ci_launcher
ci_launcher ran: https://ci.ros2.org/job/ci_launcher/9096

• Linux
• Linux-aarch64
• macOS
• Windows