Meta: Improve tools and templates

[FloEdelmann]

• The new-rule tool (npm run new) should take a second (required) command line parameter asking for the author name/username and fill that into the template automatically. Currently, many new contributors ignore that field and it needs to be raised in the review.
• The update-docs-rules-index tool (included in npm run update) should also automatically update the list of extension rules in https://eslint.vuejs.org/rules/#extension-rules. Noticed in #1996 (comment). actually seems to be already implemented.
• The Requirements, Helpers and Rule Definition comment sections are sometimes hard to follow and their benefit is negligible. Also, most contributors ignore them completely, so it needs to be mentioned manually in the review. I suggest to drop them in the new-rule tool and in every existing rule.