Support for FBA FROG analysis

[matthiaskoenig]

SBSCL has a working FBA model solver. As part of the recent HARMONY we developed basic FROG guidelines. See also https://github.com/matthiaskoenig/fbc_curation/. SBSCL should support the generation of these files for a given FBA model. This would allow to check reproducibility easily between different solvers.
The biomodels database team would apply these guidelines for FBA model curation.

[dyrpsf]

Hi @draeger and @matthiaskoenig ,
I have opened PR #102 which adds a FrogReport utility class for generating FROG
JSON reference files from SBML FBC models using the existing FluxBalanceAnalysis
implementation, plus a basic test using e_coli_core.xml.

The current implementation focuses on metadata and the primary objective, and
includes empty sections for FVA and deletion analyses as placeholders for future work.