Deepcomp

* Improved radio model: Configurable sharing/fairness models for multiple UEs connected to a BS. New default: Rate-fair sharing.
* Improved observations: Extra observation indicating the current total data rate of each UE combined over all its connections (normalized)
* New penalty for losing connection rather than disconnecting actively
* Many smaller improvements and adjustments

Details: [v0.5 details](https://github.com/CN-UPB/deep-rl-mobility-management/blob/master/docs/mdp.md#v05-improved-radio-model-week-26)

* Replaced `stable_baselines` with ray's RLlib, which is more powerful and supports multi-agent RL
* Major refactoring of most code
* No changes in radio model or MDP

Details: [MDP description](https://github.com/CN-UPB/deep-rl-mobility-management/blob/master/docs/mdp.md#v04-replaced-stable_baselines-with-rays-rllib-week-26)

* Multiple moving UEs
* Controlled by single, centralized agent that sees combined observations and takes combined actions for all UEs
* Updated radio model: Split rate among connected UEs, allow connecting from farther away, data rate of connections adds up

Details: [MDP description](https://github.com/CN-UPB/deep-rl-mobility-management/blob/master/docs/mdp.md#v03-centralized-single-agent-multi-ue-bs-selection-basic-radio-model-week-25)

* Simplest case works: Just 1 moving UE, 2+ fixed basestation.
* Simple radio model for calculating SNR based on distance to BS. Then calculate achievable data rate from SNR. Interference supported but currently disabled. No schedules yet.
* Advanced observation space using clipping and normalization (configurable)
* Baseline RL algorithm (PPO) learns to connect the UE to always at least one BS as it moves

Details: [MDP description](https://github.com/CN-UPB/deep-rl-mobility-management/blob/master/docs/mdp.md#v02-just-bs-selection-basic-radio-model-week-21)

* Simplest case works: Just 1 moving UE, 2+ fixed basestation.
* No radio/wireless model implemented yet. Instead, each BS just has a fixed radius of coverage.
* Baseline RL algorithm (PPO) learns to connect the UE to always at least one BS as it moves