Implement github actions

[gabrielenava]

I think a simple GitHub action could at least verify that:

• there are no problems in compiling the repository, even if compiling at the moment (release 2.5) simply means make install the home positions;

• the Simulink models in master are all exported in the minimum supported version (R2017b), as newer models cannot be opened in old Simulink versions.

Scheduled for the next software update 3.0.