Adaptive DMD for CSV data

[siuwuncheung]

This PR adds the capability of reading from and writing to CSV files, and introduces a functional script generic_csv.cpp to work on general CSV datasets following the file structure.

To be addressed in future PRs:

• Currently only supports serial and reproductive cases.

• While the new script is not associated with any MFEM examples, it is placed under examples/dmd along with MFEM examples. The header and the namespace of MFEM is still used. The script is only compiled with -m during build.

[kevinhkhuynh]

Can pull from master now, adaptive DMD merged.

[kevinhkhuynh]

Just to let you know, in the master branch of adaptive DMD, the order of "LS", "G" is now flipped in the constructor of AdaptiveDMD to match with the matrix_interpolation class.