Add custom rosdoc2 config for ros2_control metapackage

[christophfroehlich]

rosdoc2 will be used by the build farm to publish API docs on http://docs.ros.org/en/rolling/p/ros2_control/ which is empty now.

• remove doxyfile because it is added to control.ros.org and used here https://github.com/ros-controls/control.ros.org/pull/278
• Add custom landing page for rosdoc2: logo, links to control.ros.org
• add rosdoc2 workflow, but only if the relevant files changed

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 62.67%. Comparing base (16fbde3) to head (2559763). Report is 3 commits behind head on master.

:exclamation: Current head 2559763 differs from pull request most recent head bad52a3. Consider uploading reports for the commit bad52a3 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1484   +/-   ##
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  Coverage   62.67%   62.67%           
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  Files          96       96           
  Lines       11311    11311           
  Branches     8151     8151           
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  Hits         7089     7089           
  Misses        715      715           
  Partials     3507     3507           

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unittests	62.67% <ø> (ø)

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