Fix bugs related to the customized lmp task group submission

[wanghan-iapcm]

1. run customized command with dpgen run_command.
2. fix bug in run_command interface to dflow.utils.run_command: always non-interactive. [reverted!interactive means the bashrc file would be sourced, otherwise, not.]
3. optional parameters should be of type Parameter, BigParameter cannot be indexed.
4. link plumed input file to lammps task dir. Output plumed if they present.

[codecov[bot]]

Codecov Report

Patch coverage: 87.50% and no project coverage change.

Comparison is base (3c790bd) 88.09% compared to head (d5d46e6) 88.10%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #161 +/- ## ======================================= Coverage 88.09% 88.10% ======================================= Files 80 80 Lines 4008 4011 +3 ======================================= + Hits 3531 3534 +3 Misses 477 477 ``` | [Files Changed](https://app.codecov.io/gh/deepmodeling/dpgen2/pull/161?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=deepmodeling) | Coverage Δ | | |---|---|---| | [dpgen2/op/collect\_data.py](https://app.codecov.io/gh/deepmodeling/dpgen2/pull/161?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=deepmodeling#diff-ZHBnZW4yL29wL2NvbGxlY3RfZGF0YS5weQ==) | `96.77% <ø> (ø)` | | | [dpgen2/op/run\_dp\_train.py](https://app.codecov.io/gh/deepmodeling/dpgen2/pull/161?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=deepmodeling#diff-ZHBnZW4yL29wL3J1bl9kcF90cmFpbi5weQ==) | `98.41% <ø> (ø)` | | | [...oration/task/customized\_lmp\_template\_task\_group.py](https://app.codecov.io/gh/deepmodeling/dpgen2/pull/161?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=deepmodeling#diff-ZHBnZW4yL2V4cGxvcmF0aW9uL3Rhc2svY3VzdG9taXplZF9sbXBfdGVtcGxhdGVfdGFza19ncm91cC5weQ==) | `95.34% <66.66%> (+0.05%)` | :arrow_up: | | [dpgen2/op/run\_lmp.py](https://app.codecov.io/gh/deepmodeling/dpgen2/pull/161?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=deepmodeling#diff-ZHBnZW4yL29wL3J1bl9sbXAucHk=) | `96.58% <100.00%> (+0.05%)` | :arrow_up: |

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.