Hotfix/check permissions before chmod

[Gautzilla]

This PR should fix a bug where OSEkit unnecessarily tries to change folders/files for which it already has write/read accesses but for which it doesn't have the permission to change the permissions.

Basically, the os.chmod function should now only be called if the user doesn't have the read and write permissions to the file or folder.

@cazaudo: In the Spectrogram class, 2 files permissions were changed to the DPDEFAULT mode:
Line 1050

if not filename.exists():
  pd.DataFrame.from_records([new_params]).to_csv(filename, index=False)  
  os.chmod(filename, mode=DPDEFAULT)
  return True

Line 1065

filename.unlink()
pd.DataFrame.from_records([new_params]).to_csv(filename, index=False)
os.chmod(filename, mode=DPDEFAULT)
return True

I changed the modes to FPDEFAULT, and added a comment to keep track of that:

if not filename.exists():
  pd.DataFrame.from_records([new_params]).to_csv(filename, index=False)
  chmod_if_needed(
      path=filename, mode=FPDEFAULT
  )  # This was DPDEFAULT: was it intentional?
  return True

I'll remove the comment if you validate that the mode should be FPDEFAULT, or change back to DPDEFAULT