Refactor predictoor approach directory structure

[trentmc]

Status quo structure

- predictoor 
  - main.py, predict.py (random)
- examples
  - models
    - main.py, predict.py (load static model)

Problems:

• random approach doesn't specify that it's random
• then two (!) directories down where models go
• and it doesn't give much space for different approaches to models. Eg static model (load from file) vs dynamic model (build on-the-fly) vs other future variants

Proposed solution structure

- approach1
    - main.py, predict.py (random)
- approach2
    - main.py, predict.py (load pre-built model)
- approach3
    - main.py, predict.py (build model on-the-fly)