make native MD compatible with v2.0

[njzjz]

Although no one really enables and uses it, I still make it compatible with v2.0.
Also fix compilation errors.
Seems there is hard-code DOUBLE in the code, and I have no time to fix it, so I comment the build for float precision.

[codecov-commenter]

Codecov Report

Merging #950 (88eb5c2) into devel (5529a97) will decrease coverage by 7.79%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##            devel     #950      +/-   ##
==========================================
- Coverage   83.30%   75.51%   -7.80%     
==========================================
  Files         118       85      -33     
  Lines        9982     6796    -3186     
==========================================
- Hits         8316     5132    -3184     
+ Misses       1666     1664       -2     

Impacted Files	Coverage Δ
source/api_cc/tests/test_deepdipole.cc
source/lib/tests/test_prod_force_r.cc
source/lib/tests/test_simulation_region.cc
source/lib/tests/test_prod_force_grad_r.cc
source/api_cc/tests/test_deeppot_model_devi.cc
source/lib/tests/test_soft_min_switch_force.cc
source/lib/tests/test_neighbor_list.cc
source/lib/tests/test_coord.cc
source/lib/tests/test_gelu.cc
source/lib/tests/test_prod_virial_a.cc
... and 23 more

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