Definition of 'data' throughout flepiMoP and documentation

[saraloo]

In submission scripts we call on an environmental variable DATA_PATH that refers to the project repository (eg Flu_USA or COVID19_USA). Got confused while writing up some instructions as some model running instructions refer to a data repository, while refer to a project repository. I think we should switch to calling it project repository (within that there is some data input folder).

Propose a change from DATA_PATH to PROJECT_PATH or something? This is only used in submission scripts from what I can tell.

As a more general question (I think @alsnhll has brought this up in the past) - but what is the general approach to what we call data?