RFE Board (Face expressions) - Implement test

[valegagge]

As asked here, we need to create a test for validating the face expressions boards (RFE).

Dod

Test implemented and validated.

[valegagge]

old procedure : https://mesh-iit.github.io/procedures/tp-old-face-expressions/?h=face#33-test-servo-motor-and-leds

FACE EXPRESSION V1.0 - MESH Test Procedures

Documentation resources for test procedures

[MSECode]

Hi @valegagge,
considering the old procedure. Since we had some problem executing it lately while working on: robotology/mesh-support#2301 it is best to updated it. I can proceed on that since together w/ @edersonferrante we noted some points to improve. I've already opened an issue under procedures.