Refactoring

Refactoring the code including (removing redundant codes, renaming variables, documenting functions, etc):

• IMP: #33 (closed)
• parameters.py
• All the server files
  • Update caching for deletion after sobol computations
  • Reduce the code size
  • Privatize attributes and methods
  • Docstrings for each method in a markdown format.
  • Final results with MPI_Gatherv instead of P2P communication
  • In SA study, during result gatherings, the vector sizes were not being calculated per field. Now fixed.
• reservoir.py
  • optimizations to the data structures TBD in a new branch later.
• Propagate changes to all user-defined server files pytests
  • Merge CI-improvements to develop and then put those changes in this branch.
• JSON configurations
  • Update all json files with new options
  • Write the schema for new options in melissa/launcher/schema.py.
• Merge bruno-dev here.