Migrate Tiago gazebo classic simulation to the new gazebo

[Rezenders]

• Migrate sdf
• Migrate plugins
• Update launch files

Follow-up on this issue: pal-robotics/tiago_simulation#27

[Rezenders]

@EGAlberts @fghzamani could you list which forked repos you are using for this?
If it makes it easier to collaborate we could create the forks in the kas-lab organization. Let me know if you want to do that and you don't have access.
Also, if you need someone to test something or help with a specific sub-task let me know