Reorganize the project structure

[pvk-developer]

Due to a structure that is making it hard to implement new hyperparameters and confusing at the same time, a lac of documentation and other issues that makes working with BTB complicated, a new structure is being proposed as follows:

• Hyperparameter: A base class that defines an abstraction for all the hyperparameters (see the structure below). New hyperparameters can inherit from this class for a simple and quick implementation, having the base types of each class holding it's corresponding hyperparams (boolean, categorical, numerical...) each one in a separated file.
• Tunable class which holds a collection of hyperparameters with metadata such as contraints and conditions and this class being able to interact with all of the hyperparameters defined.
• Acquisition Function, which will be a mixin that the Tuner class will have to extend a long side of an MetaModel which will also be a mixin.
• MetaModel, a mixin that defines the model and it's private functions such as _fit and _predict which are public at the moment but the final user should not have to use them directly.
• Tuner, a class that will inherit from the mixins explained above, will have an abstract class which will implement : best_score, best_params as properties (which are not documented at the moment and are private). This class will work with a single object Tunable instad of a list. Also, some rename of the methods, like add, to record to reflect better it's function should be made.

The new project structure would be similar to this:

├── btb
│   ├── __init__.py
│   ├── selection
│   │   └── __init__.py
│   └── tuning
│       ├── acquisition
│       │   └── base.py
│       ├── hyperparams
│       │   ├── base.py
│       │   └── __init__.py
│       ├── __init__.py
│       ├── metamodels
│       │   ├── base.py
│       │   └── __init__.py
│       ├── tunable.py
│       └── tuners
│           ├── base.py
│           └── __init__.py