Add new write result function

[timeforplanb123]

write_result:

• function writes Result object to file
• write_result returns diff between old file and new file (str)
• parameters:
  • filename - file you want to write the result. write_result creates dirs with filename if it's necessary
  • vars, failed, severety_level
  • write_host - write hostname to file or not
  • count is the same that count from print_result. It's number of sorted results (-5 or 5, for example). It can be useful for a large number of identical results. It's acceptable to use numbers with minus sign(-5 as example), then results will be from the end of results list.
  • append - "a+" or "w+" mode
  • no_errors - dont't write result with errors to file

[dbarrosop]

Same as with other PRs, commits are mixed somehow

[timeforplanb123]

Replaced all new functions to single PR with ipynb examples #21