remove get_all_params()

[zekunlou]

For #100.

Function ParseConfig.get_all_params() is removed.

In each python script:

• if a parameter is only used a few times, then it will be called via inp.xxx;
• otherwise if it is used over and over again (e.g. inp.gpr.Menv is reused for 12 times in minimize_loss.py), its value will be assigned to a short but clear-named local variable.
  • Also for minimizing the changes introduced to the code.

Tested on FHI-aims water monomer example and passed.