Imported a few libraries and corrected minor errors to run the mappin…

[bayonato89]

Imported a few libraries and corrected minor errors to run the mapping_GEAR1 function

Type of change:

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works

[pabloitu]

The tests of this PR are being blocked because of https://github.com/SCECcode/pycsep/blob/5f84ea97101de0439deb1e3f5c383874c7bb3801/csep/utils/plots.py#L7. It needs to be updated to:

from scipy.integrate import cumulative_trapezoid