Describe the bug
When trying to use the "Generate" function over the docx document from the pipeline DOCUMENTS tab - two files are downloaded to the local machine, both with the same name, one file is the same as the original docx document and the second contains only the error instead of the document content

To Reproduce
Steps to reproduce the behavior:

1. Open any pipeline, select the DOCUMENTS tab
2. Upload the document with docx extension
3. Click the Generate button next to the uploaded document
4. Wait until files will be downloaded
5. Open the smaller file in any text editor
6. See the error: {"message":"Error while executing command python /usr/lib/python2.7/site-packages/scripts/deps_graph.py /opt/api/workspace/git7009710166274989972 config.json: \nTraceback (most recent call last):\n File \"/usr/lib/python2.7/site-packages/scripts/deps_graph.py\", line 108, in <module>\n main_file, main_class = parse_config(config, config_name)\n File \"/usr/lib/python2.7/site-packages/scripts/deps_graph.py\", line 91, in parse_config\n return get_main_file_class(item['configuration'])\n File \"/usr/lib/python2.7/site-packages/scripts/deps_graph.py\", line 96, in get_main_file_class\n return config['main_file'][:-3], config['main_class']\nKeyError: 'main_file'","status":"ERROR"}

Expected behavior
More convenient and clear error message

Environment:

• Cloud Provider: N/A
• Version: 0.16.0.3326.baa436998d5541afca887e14746c1db3bc8bcd39
• Browser: chrome, Mozilla Firefox, MS Edge