update csv to parquet to use multiprocessing

[JoshCu]

Multiprocessing for Faster Input Reformatting

When testing routing for 6500 catchments and 24 timesteps, a large portion of the troute execution time is still spent on reformatting ngen output. PR #714 partially addressed this issue with an awk command. This PR adds multiprocessing to speed it up even more.

Performance Comparison

Without Multiprocessing

************ TIMING SUMMARY ************
----------------------------------------
Network graph construction: 0.8 secs,  7.27%
Forcing array construction: 7.7 secs, 69.93%
Routing computations:      1.89 secs, 17.20%
Output writing:            0.61 secs,  5.56%
----------------------------------------

With Multiprocessing (56 cores - default to CPU core count)

************ TIMING SUMMARY ************
----------------------------------------
Network graph construction: 0.84 secs, 19.68%
Forcing array construction: 0.98 secs, 22.94%
Routing computations:      1.82 secs, 42.92%
Output writing:            0.61 secs, 14.36%
----------------------------------------

With Multiprocessing (4 cores - hardcoded example)

************ TIMING SUMMARY ************
----------------------------------------
Network graph construction: 0.79 secs, 14.09%
Forcing array construction: 2.36 secs, 42.39%
Routing computations:       1.8 secs, 32.29%
Output writing:            0.62 secs, 11.15%
----------------------------------------

Notes

• This works in ngiab with ngen run serially,
• Testing this via ngen with MPI will actually reduce performance due to an issue being worked on in NOAA-OWP/ngen#846.
• Building ngen from that PR should work.
• An ngiab image for x86 with both the MPI patch and this troute patch applied is available at joshcu/ngiab_dev.