Add randomized goal option

[andrearitossa]

Added randomized goal:

• Implemented a randomized_goal parameter that allows for goal pose randomization
• When enabled, the goal position (x,y) and orientation are randomly sampled within the environment boundaries
• Added proper margins for the goal position to be at a reasonable distance from the walls

[moribots]

I think you will need to add an option to change the conditioning to include the goal information visa pose.

This will necessitate an update to obs_type so that a new appropriate dataset can be generated

Otherwise, the agent will not be able to learn the harder task.

[andrearitossa]

True!
I added the goal directly inside ´obs_type´s: ´state´ and ´environment_state_agent_pos´.

How does it look?

[moribots]

minor nit :) thanks for doing this!

[andrearitossa]

Thank you for the review!