Add class to Stoch files

[lispandfound]

This PR introduces a new module to read stoch files. This is useful for debugging HF runs.

Summary of the StochFile class:

• Reads and parses stochastic slip model files, extracting data about fault planes.
• Provides access to key plane properties, including:
  • planes: A list of Plane objects representing the fault geometry.
  • slip: A list of 2D numpy arrays containing slip values for each plane.
  • patch_centres: A list of 2D numpy arrays containing the geographic coordinates of patch centres.
  • rise: A list of 2D numpy arrays containing rise time values.
  • trup: A list of 2D numpy arrays containing rupture time values.

I have extracted some functions from the srf module for common functionality with the stoch module

[lispandfound]

See the wiki for a description of the stoch file format.

[sungeunbae]

Excellent