Update maintainers and add url tags

[christophfroehlich]

The contents of the package.xml get parsed for index.ros.org, so I thought it might be worth updating them.

• Update the current maintainers
• Where possible, I added the original authors as <author>
• add url tags, but only to github and control.ros.org homepage. The direct links to the controllers have the ROS distro in the URL, that would soon become outdated.

[saikishor]

Few minor changes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.87%. Comparing base (f519170) to head (8b1e67c).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1363      +/-   ##
==========================================
- Coverage   80.89%   80.87%   -0.03%     
==========================================
  Files         109      109              
  Lines        9696     9699       +3     
  Branches      842      845       +3     
==========================================
  Hits         7844     7844              
  Misses       1574     1574              
- Partials      278      281       +3     

Flag	Coverage Δ
unittests	80.87% <ø> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

see 3 files with indirect coverage changes

[fmauch]

This looks good and I checked that

$ xmllint --noout --schema http://download.ros.org/schema/package_format3.xsd */package.xml
ackermann_steering_controller/package.xml validates
admittance_controller/package.xml validates
bicycle_steering_controller/package.xml validates
diff_drive_controller/package.xml validates
effort_controllers/package.xml validates
force_torque_sensor_broadcaster/package.xml validates
forward_command_controller/package.xml validates
gripper_controllers/package.xml validates
imu_sensor_broadcaster/package.xml validates
joint_state_broadcaster/package.xml validates
joint_trajectory_controller/package.xml validates
parallel_gripper_controller/package.xml validates
pid_controller/package.xml validates
pose_broadcaster/package.xml validates
position_controllers/package.xml validates
range_sensor_broadcaster/package.xml validates
ros2_controllers/package.xml validates
ros2_controllers_test_nodes/package.xml validates
rqt_joint_trajectory_controller/package.xml validates
steering_controllers_library/package.xml validates
tricycle_controller/package.xml validates
tricycle_steering_controller/package.xml validates
velocity_controllers/package.xml validates

[bmagyar]

Thank you so much!