[rviz_common] use port/alternative to pluginlib

[wjwwood]

Much of the plugin related loading of displays, tools, and view controllers is currently disabled. Once we have a solution for pluginlib, we should re-enable these by using that alternative.

Here are some examples:

• rviz/rviz_common/src/rviz_common/display_factory.hpp

  Line 31 in ca8f42e

  // TODO(wjwwood): revist this file when pluginlib solution found

• rviz/rviz_common/src/rviz_common/display_group.cpp

  Line 39 in ca8f42e

  // TODO(wjwwood): reenable this when pluginlib solution found

• rviz/rviz_common/src/rviz_common/pluginlib_factory.hpp

  Line 30 in ca8f42e

  // TODO(wjwwood): refactor this to work with ROS 2

• rviz/rviz_common/src/rviz_common/tool_manager.cpp

  Lines 220 to 221 in ca8f42e

  	// TODO(wjwwood): make this load a particular tool, until plugin loading is
  	// implemented, then restore functionality.

• rviz/rviz_common/src/rviz_common/tool_manager.hpp

  Line 40 in ca8f42e

  // TODO(wjwwood): restore pluginlib_factory when possible

• rviz/rviz_common/src/rviz_common/view_manager.hpp

  Lines 40 to 41 in ca8f42e

  	// TODO(wjwwood): replace usage of pluginlib_factory
  	// #include "./pluginlib_factory.hpp"

• rviz/rviz_common/src/rviz_common/view_manager.cpp

  Line 52 in ca8f42e

  // factory_(new PluginlibFactory<ViewController>("rviz", "rviz::ViewController")),

And certainly other places with a similar comment out and todo pattern.

I'll take this one on, as well as finding a pluginlib solution.

[wjwwood]

Fixed in #123.