fix submodule url

[test] update use of example_robot_data to 3.8.0

update deprecations & fix warnings

fix:
…/sot-core/src/tools/device.cpp: In member function ‘virtual void dynamicgraph::sot::Device::setState(const Vector&)’:
…/sot-core/src/tools/device.cpp:248:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
       }
       ^
…/sot-core/src/tools/device.cpp:249:5: note: here
     case CONTROL_INPUT_ONE_INTEGRATION:
     ^~~~

fix:

…/sot-core/src/tools/robot-utils.cpp: In member function ‘void dynamicgraph::sot::RobotUtil::sendMsg(const string&, dynamicgraph::MsgType, const string&)’:
…/sot-core/src/tools/robot-utils.cpp:449:49: warning: ‘void dynamicgraph::Logger::sendMsg(std::__cxx11::string, dynamicgraph::MsgType, const string&)’ is deprecated: use stream(type, lineId) << msg [-Wdeprecated-declarations]
   logger_.sendMsg("[RobotUtil]" + msg, t, lineId);
                                                 ^
In file included from …/sot-core/include/sot/core/robot-utils.hh:23:0,
                 from …/sot-core/src/tools/robot-utils.cpp:29:
…ll/include/dynamic-graph/logger.h:225:3: note: declared here
   sendMsg(std::string msg, MsgType type, const std::string &lineId = "");
   ^~~~~~~
…/sot-core/src/tools/device.cpp: In member function ‘virtual void dynamicgraph::sot::Device::setState(const Vector&)’:
…/sot-core/src/tools/device.cpp:248:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
       }
       ^
…/sot-core/src/tools/device.cpp:249:5: note: here
     case CONTROL_INPUT_ONE_INTEGRATION:
     ^~~~

[Device] Make error message more informative.

[Tests][CMake] activate python imports checks

to be compliant with unittest standard and ease discovery
ref. https://docs.python.org/3/library/unittest.html#cmdoption-unittest-discover-p

[tests] rename data do disambiguate for C++17

the install rpath allow plugins to find each other

ROS buildfarm test everything in isolated environments, se we must also
set the build rpath

[Tests] matlab reference was removed

ref. https://github.com/stack-of-tasks/dynamic-graph-python/pull/74