Update pspm document generation functions for new website

[teddychao]

Update documentation generation function for new website design.

Key updates:

1. The previous version incorrectly put the line of options in the previous line, and the new version has added a newline break correctly.
2. The new version updated the format of generated markdown files by following the requirement of the new PsPM website.
3. The filenames of generated markdown files are now with a date in the beginning for meeting requirement.

• The date can be used for ranking the list in the content if necessary.

[teddychao]

Example of generated file, now following the new website style correctly

[teddychao]

I will use another pull request for updating the documentation of the website design and also updating the document for pspm_gen