Search by pattern, search for file names(including extension) with fnmatch module, support for Unix shell-style wildcards

[NataliaBondarenko]

Changes related to previous discussions.
Search by other criteria:
#88
Search by pattern also allows you to search for several similar extensions(partially):
#92

• added def search_files_by_pattern
  search for file names(including extension) using Unix shell-style wildcards: *, ?, [seq], [!seq];
  used fnmatch.fnmatch(filename, pattern) and fnmatch.fnmatchcase(filename, pattern) from PSL https://docs.python.org/3/library/fnmatch.html;
  result is a generator with full paths.

• added new argument --filename-match PATTERN as part of parser search group
  if you use this argument, common args and special search group arguments are available (preview, previw-size, file-sizes);
  except for the --file-extension argument, which is used separately;
  preview behavior is similar to --file-extension .. (all extensions),
  in this case, the preview will only be displayed for files with a supported extension.

• updated help_text, start message for CLI, SUPPORTED_TYPE_INFO_MESSAGE

• added test

Examples:
count-files --filename-match *test* returns files with word test in filename
count-files --filename-match setup.py returns exact file
count-files --filename-match *.py? returns files with extensions .pyc, .pyo, .pyd, .pyw and so on

[victordomingos]

Great work you have done here. Thanks!