Chemistry update

[doraemonho]

Prerequisite checklist

• [x] My code follows the Athena++ Style Guide
• [ ] My change requires a change to the documentation.
• [ ] I have updated the docume
• [ ] ntation in the Wiki accordingly.
• [x] I have added tests to cover my changes.
• [x] All new and existing tests passed.

Please review the CONTRIBUTING.md file for detailed guidelines.

Description

A new chemistry network (from Grassi et al. (2014), later called G14) is added to the chemistry module

Major :

1. New network file G14Sod.cpp/ G14Sod.hpp is added under src/chemistry/network
2. New problem generator file chem_G14Sod.cpp is added under src/pgen
3. New input file athinput.chem_G14Sod is added under inputs/chemistry/
4. New regression file chem_G14Sod.py is added under /tst/regression/scripts/tests/chemistry
5. New regression data file chem_G14Sod_dt_2.5e-3.vtk is added under /tst/regression/data

Minor :

1. configure.py is changed for adding the configuration of the new network
   • prefix "G14Sod" is added for the chemistry network
   • "NUMBER_CHEMICAL_SPECIES" is defined for "G14Sod"
2. typo correction in unit.cpp , now it will fix the error for using the custom unit system
   The test was ran at NERSC's Perlmutter CPU node

Potential conflict: cflag changed from C++11 to C++14 standard due the requirement of the newest version of CVODE library.