Add the possibility to show labels on the headset

[S-Dafarra]

It is possible to add multiple labels to the VR view. For each label it is possible to specify:

• the width and height dimensions of the enclosing box
• the position of the box
• a prefix string, that is prepended to whatever is read on the corresponding port
• a suffix string
• the pixel size of the label
• the color of the label (RGBA)
• the background color (RGBA)
• the font
• the horizontal and vertical alignment
• whether the box should appear at startup, or only after some data is received on the port
• the timeout after which the box automatically disappear (negative to have no timeout)

In addition, it is possible to enable/disable the label manually from RPC

This depends on #10

[traversaro]

Minor comment.

[S-Dafarra]

I am going to merge this after #10

[S-Dafarra]

Rebased on top of rpc.

[S-Dafarra]

@kouroshD @traversaro @RiccardoGrieco please let me know if I can proceed!

[traversaro]

Ok for me!

[kouroshD]

Sounds good to me @S-Dafarra !

[S-Dafarra]

Thanks a lot @kouroshD @traversaro. Merging

[S-Dafarra]

I realized later that I merged in rpc. I manually merged in main.