Adapt controller Reference/StateInterfaces to New Way of Exporting (variant support)

[mamueluth]

This PR is the fith and last part of multiple breaking down #1240 in smaller changes. For an overview explanation and a lot of comments/discussion, please refer to #1240.
This PR adapts the controller interface to the new way of exporting Reference and StateInterfaces. ReferenceInterfaces now are created as shared_ptr and shared to controller manager as shared_ptr. The memory is still allocated in the controller (old way) but a unordered_map for the interfaces is added.

• Needs Adapt test to new way of exporting reference interfaces (Related to #1240 in ros2_control) ros2_controllers#1103 to be merged as well

NOTE: Everything is fully backward compatible at this point. At this point variant supports only double at this point.

[mergify]

This pull request is in conflict. Could you fix it @mamueluth?

[bmagyar]

I've rebased this PR, you can find a backup of it on https://github.com/StoglRobotics-forks/ros2_control/pull/new/controller_interface_variant_support_base_BAK

[codecov]

Codecov Report

Attention: Patch coverage is 59.79381% with 39 lines in your changes missing coverage. Please review.

Project coverage is 86.95%. Comparing base (ce5c35a) to head (59530e2).
Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
...r_interface/src/chainable_controller_interface.cpp	49.25%	30 Missing and 4 partials ⚠️
controller_manager/src/controller_manager.cpp	50.00%	4 Missing ⚠️
controller_interface/src/controller_interface.cpp	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1689      +/-   ##
==========================================
- Coverage   87.19%   86.95%   -0.24%     
==========================================
  Files         118      118              
  Lines       11369    11430      +61     
  Branches     1049     1051       +2     
==========================================
+ Hits         9913     9939      +26     
- Misses       1094     1125      +31     
- Partials      362      366       +4     

Flag	Coverage Δ
unittests	86.95% <59.79%> (-0.24%)	⬇️

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

Files with missing lines	Coverage Δ
...oller_interface/chainable_controller_interface.hpp	100.00% <ø> (ø)
...lude/controller_interface/controller_interface.hpp	100.00% <ø> (ø)
...controller_interface/controller_interface_base.hpp	90.00% <ø> (ø)
...rface/test/test_chainable_controller_interface.cpp	100.00% <100.00%> (ø)
...de/hardware_interface/loaned_command_interface.hpp	100.00% <100.00%> (ø)
...lude/hardware_interface/loaned_state_interface.hpp	75.00% <100.00%> (+8.33%)	⬆️
hardware_interface/src/resource_manager.cpp	73.39% <100.00%> (-0.27%)	⬇️
...e_interface_testing/test/test_resource_manager.cpp	99.32% <100.00%> (ø)
controller_interface/src/controller_interface.cpp	75.00% <50.00%> (ø)
controller_manager/src/controller_manager.cpp	77.31% <50.00%> (-0.17%)	⬇️
... and 1 more

[saikishor]

Overall the PR looks good to me. Thanks for the great work @mamueluth @bmagyar 👏🏾

I've found minor things to be addressed apart from the suggestion from this review, but I can open up a following PR to address them.

[bmagyar]

@saikishor separate PR please

[saikishor]

@saikishor separate PR please

Sure, I will do that :)
I will open it once this is merged.

[destogl]

Let's add Test for this!