New input method for ONEFlux

[toanngosy]

Proposal

Unify the parameters file into a single run file, .i.e .yaml file.

Motivation

At the moment, the run parameters of ONEFlux are spread across different methods: from local_settings.py and from command arguments.
I propose to have all configurable parameters in a single configuration file so it is easy to share and reproduce each run.
The YAML file is a good candidate since it is easy to read and has been widely adopted as a configuration file in many projects.

Pros

• The YAML format is easy to read.
• It has indentation syntax for the hierarchical structure that is similar to Python syntax.

Cons

• Need to install PyYAML library.
• Extra precaution when modifying the YAML file because a single mismatch indentation can mess up the configuration file. However, users may want to use the provided YAML template.

Plan

• Add PyYAML library to requirements.txt.
• Add template YAML file.
• User can provide the YAML file and overwrite it with command arguments.
• Save run parameters.
• Merge local_settings.py with the new configuration file.

[toanngosy]

@gilbertozp This is addressed in #38