Workfiles tool: Fix work with anatomy templates

[iLLiCiTiT]

Changelog Description

Workfiles tool uses anatomy templates correctly.

Additional info

The issue was caused by #190 . It did use template string when it should use object and opposite. Added few docstrings and comments.

Testing notes:

1. Workfiles tool is able to save workfile (e.g. using Save As button).

[BigRoy]

Can confirm this fixes this error:

Traceback (most recent call last):
  File "E:\dev\ayon-core\client\ayon_core\tools\workfiles\widgets\files_widget.py", line 253, in _on_workarea_save_clicked
    result = self._exec_save_as_dialog()
  File "E:\dev\ayon-core\client\ayon_core\tools\workfiles\widgets\files_widget.py", line 175, in _exec_save_as_dialog
    dialog.update_context()
  File "E:\dev\ayon-core\client\ayon_core\tools\workfiles\widgets\save_as_dialog.py", line 237, in update_context
    data = self._controller.get_workarea_save_as_data(folder_id, task_id)
  File "E:\dev\ayon-core\client\ayon_core\tools\workfiles\control.py", line 410, in get_workarea_save_as_data
    return self._workfiles_model.get_workarea_save_as_data(
  File "E:\dev\ayon-core\client\ayon_core\tools\workfiles\models\workfiles.py", line 683, in get_workarea_save_as_data
    return self._workarea_model.get_workarea_save_as_data(
  File "E:\dev\ayon-core\client\ayon_core\tools\workfiles\models\workfiles.py", line 310, in get_workarea_save_as_data
    comment_hints, comment = self._get_comments_from_root(
  File "E:\dev\ayon-core\client\ayon_core\tools\workfiles\models\workfiles.py", line 244, in _get_comments_from_root
    matcher = CommentMatcher(extensions, file_template, fill_data)
  File "E:\dev\ayon-core\client\ayon_core\tools\workfiles\models\workfiles.py", line 47, in __init__
    fname_pattern = file_template.format_strict(temp_data)
AttributeError: 'str' object has no attribute 'format_strict'

Tested in Houdini 20.