Design first version of framework

[knoepfel]

DUNE US S&C R&D item 062, 063, and 066

The framework design must include:

• Enumeration of core framework systems
• Definition of the interaction between core framework and IO backends
• The conceptual model of the framework workflow, which cover things like:
  1. What does the user specify? The data to be produced, the input data, and the algorithms?
  2. Form various textual descriptions proposing ways of doing this.
  3. What is the framework configuration schema? How does the user specify what work needs to be done?

The proposal for documenting the design (with @greenc-FNAL as documentation czar):

• The document must be version-controlled
• We should favor human-readable diagram specifications
• Let's use Sphinx for automatically-generated reference (API) documentation
• Let's use Sphinx to produce both user documentation and design documents
• Ideally, we'd use something that is amenable to an eventual publication-quality document