Implement Fama and French Three Factor Model

Add a `fama_and_french_three_factor_model` function to `stonks/processing/models.py`. For formula details, see [here](https://www.investopedia.com/terms/f/famaandfrenchthreefactormodel.asp).

- The function takes only the relevant formula parameters as arguments.
- The function returns the Total Return of a Stock.
- All percentages are represented as decimals (ie. 9% is represented 0.09)
- Arguments and return shall be type hinted (will almost certainly be `float` in most cases. See other functions in `stonks/processing/models.py` for type hinting examples).
- Exactly one unit test shall be written for this function called `test_arbitrage_pricing_theory` in `test/processing/test_models.py`.[

[This](https://hackernoon.com/calculate-required-rate-of-return-with-the-fama-french-three-factor-model-0k1d31ww) may also be helpful/relevant.