Release v0.2 - Githubissues

Summary

This PR does the following:

Added DiambraWrapper
Added Multi-encoder/decoder to all the algorithms, but Droq, Sac and PPO Recurrent
Added Multi-discrete support to PPO, DreamerV1 and P2E-DV1
Modified the make_env function to be able to train the agents on environments that return both pixel-like and vector-like observations
Modified the ReplayBuffer class to handle multiple observations
Updated howtos
Fixed both #40 and #66
Logger creation is moved to sheeprl.utils.logger
Env creation is moved to sheeprl.utils.env
PPO algo is now a single-folder algorithm (removed ppo_pixel and ppo_continuous folder)
sac_pixel has been renamed to sac_ae
Added support to gymnasium==0.29.0, mujoco>=2.3.3 and dm_control>=1.0.12

Please select the one relevant option below:

Breaking change (fix or feature that would cause existing functionality to not work as expected)

Please confirm that the following tasks have been completed:

[x] I have tested my changes locally and they work as expected. (Please describe the tests you performed.)
[x] I have added unit tests for my changes, or updated existing tests if necessary.
[x] I have updated the documentation, if applicable.
[x] I have installed pre-commit and run locally for my code changes.