Fix research function to work without an algorithm file

[Marinovsky]

Closes #491

The algorithm name is just used to create the configurations for lean and the docker container in the research() function. The content of the file is never used, and it doesn't even need to exist. Thus, I added an optional argument in project_manager.find_algorithm_file to not throw an exception when the file is not found but instead return None. Then, if the result is None we just use a default python algorithm file name for the variable algorithm_file so that we can create the configs we need.

[Martin-Molinero]

Thank you! 👍