Reopening of PR 363

[jbdelmundo]

Reopening from PR 363

Description
Added the following changes:

• Docstrings in BaseStrategy
• Added a new logging module instead of simply doing print() inside the BaseStrategy
• Logging inside the strategy can be accessed using self.logging.log()
• Separated the function of adding periodic cash
• buy_signal() and sell_signal() can now return (signal, buy/sell_prop) instead of just boolean (still backwards compatible)
• Added trade_history
• Set default signal to False (no action)

Checklist
[ X] I am making a pull request from a branch other than master
[ X] I have read the CONTRIBUTING.md
[ X] I have added/edited documentation in a relevant docs/docusaurus markdown file
[X ] (For new docs, check if not applicable) I have added the id of a new docs md to the docs/docusaurus/sidebars.js file

[mikeejazmines]

hi @jbdelmundo! Sorry for the delay, am reviewing your PR now but could you fix all the merge conflicts? I agree with the implementation and can merge this once the merge conflicts are fixed and when I'm done reviewing and testing everything else :)

Thanks so much!