ROS2: Use rosbag2_py Python API, remove all explicit SQLite3 logic

[emersonknapp]

Description

The current implementation of rqt_bag for ROS 2 does not allow for different storage implementations, it is explicitly implemented as a SQLite3 reader. Til now this was not a large concern, but as MCAP gains usership, this will become more of a concern. The rosbag2_py API is intended to be a generic interface to ROS 2 bag access and manipulation. Anything that rqt_bag needs, that rosbag2_py does not provide, needs to be added as part of completion of this ticket.

Completion Criteria

• No more direct dependency on sqlite3 - should not see that exact string anywhere in the
• Feature parity when opening .mcap files, with anything that can currently be done with .db3 files

[emersonknapp]

• This seems self-contained to rosbag2.py, which doesn't have that much code, luckily.
• sqlite3 is a python builtin, so there won't be any dependency to remove
• Though it would be nice to move some of the e.g. Recorder logic to rosbag2_py as well, that'll be out of scope for this ticket

[emersonknapp]

Progress tracking:

• [x] https://github.com/ros-visualization/rqt_bag/pull/123
• [x] https://github.com/ros2/rosbag2/pull/1082
• [x] https://github.com/ros2/rosbag2/pull/1083
• [x] https://github.com/ros-tooling/rosbag2_storage_mcap/pull/54
• [x] https://github.com/ros2/rosbag2/pull/1098
• [x] https://github.com/ros-visualization/rqt_bag/pull/126

[emersonknapp]

Followup work - not strictly necessary but required for reasonable performance:

• [ ] https://github.com/ros2/rosbag2/pull/1117

[emersonknapp]

Closing as feature-complete, will finish up that followup separately