Adds BSD-3 licensed ANYmal C simple description from
https://github.com/ANYbotics/anymal_c_simple_description commit
f119c8f3c4b9e08948b0f5915e9c7cedf63f52e5

Modified to:
1. Fix the path for mesh loading
2. Add SRDF

* cassie/cassie_v2 sdf: remove first primatic joint, add color information

* robots_loader: use updated sdf parser for pin version > 2.9.1

* cassie srdf: update joint info, add missing joints

Co-authored-by: Rohan Budhiraja <proyan@users.noreply.github.com>

* Add simplified double pendulum

* Add description to urdf, loader and unittest

* Fix format

* Fix format for unittest

* double pendudum: update credits

Co-authored-by: Justin Beri <justin [dot] beri [at] csiro [dot] au>
Co-authored-by: Justin Beri <justin.beri at hdr.qut.edu.au>
Co-authored-by: Guilhem Saurel <guilhem.saurel@laas.fr>

* added Articulated soft robot loader and description

* removed the unneccesary files and the deprecated loader function

* added license and readme

* renamed the readme file and added these files in twodof robot description

* remove use less file

* remove useless file

* Update test_load.py

* removed useless folder and plugins from the urdf

Co-authored-by: Justin Carpentier <justin.carpentier@inria.fr>

* Make double_pendulum's joints unbounded revolute (continuous)

* Add continuous (SO(2)) variant of double_pendulum

* Remove update to deprecated function; inherit from DoublePendulumLoader

* Add unit test

* [cassie_description] initial commit

* [cmake] update

* [cassie.sdf] change mesh path relative to example-robot-data

* [cassie_description] move meshes up folder

* [cassie-loader] create loadCassie function for load with sdf

* cassie srdf: standing pose

* [cassie_loader] use robotloader

* add unittest. won't yet work before pinocchio3

* Update unittest/test_load.py

Co-authored-by: Guilhem Saurel <guilhem.saurel@laas.fr>

* ci fixes: flake8 + unittest missing module

* fix test

Co-authored-by: Rohan Budhiraja <proyan@users.noreply.github.com>
Co-authored-by: Guilhem Saurel <guilhem.saurel@laas.fr>

* [loader] SDF support

Co-authored-by: Guilhem Saurel <guilhem.saurel@laas.fr>

* [bugfix] Included the velocity limits in the talos-legs model