Add conda-based CI on Windows, macOS and Linux

[traversaro]

With some logic taken from robotology/idyntree-yarp-tools#17 to compile YARP from source in devel branch, at least for now.

[traversaro]

Compilation works. The ControlBoardControlTest tests seems to be flaky on Conda/Linux, as it happens with Apt-provided Gazebo.

macOS tests are failing instead with:

Test project /Users/runner/work/gazebo-yarp-plugins/gazebo-yarp-plugins/build
    Start 1: ControlBoardControlTest
1/2 Test #1: ControlBoardControlTest ..........***Exception: SegFault 13.70 sec
[==========] Running 4 tests from 1 test case.
[----------] Global test environment set-up.
[----------] 4 tests from PhysicsEngines/ControlBoardControlTest
[ RUN      ] PhysicsEngines/ControlBoardControlTest.PluginTest/0

    Start 2: RobotInterfaceTest
2/2 Test #2: RobotInterfaceTest ...............***Exception: SegFault  0.45 sec
[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from PhysicsEngines/RobotInterfaceTest
[ RUN      ] PhysicsEngines/RobotInterfaceTest.PluginTest/0


0% tests passed, 2 tests failed out of 2

Total Test time (real) =  14.18 sec

The following tests FAILED:
	  1 - ControlBoardControlTest (SEGFAULT)
	  2 - RobotInterfaceTest (SEGFAULT)
Errors while running CTest

While on Windows the tests hangs:

Test project D:/a/gazebo-yarp-plugins/gazebo-yarp-plugins/build
    Start 1: ControlBoardControlTest

Given this, I think it is ok to disable tests for now on macOS and Windows.

[traversaro]

@ste93 I added this so we are sure that all the future refactoring are not going to create compilation problems.