www-site: Replace JS date formatting with Pelican + fix hero

[DrGreekenstein]

This PR removes the JS date formatting, fixes an unclosed div tag and removes the duplicate src attribute in an image.
Issue - "Why assume US date format? #565"

Please feel free to review or adjust as needed.

[sebbASF]

Sorry, but the proposed solution does not work.
The website is built with Pelican, not Hugo.
The new lines after '[for foundation]' and before '[end]' cause the html to be treated as text.

Also please do not mix independent changes in a single PR.

[DrGreekenstein]

i am really sorry for overlooking that detail, i will correct and submit again

[sebbASF]

The PR still includes the hero fix (which I put in a separate PR) - please remove it.

Also, this page uses ezt templating; this needs to be retained or there will likely be issues.

Have you tested the changes?

[sebbASF]

I created a preview branch at https://github.com/apache/www-site/tree/preview/issue-565
This is a copy of main, but using index.ezmd from this PR.

The resulting site can be seen at:
https://www-issue-565.staged.apache.org/

There are a couple of issues with the output:

• https://www-issue-565.staged.apache.org/index.html#upcoming-events shows 2 past events. This is because the base for the PR is out of date compared with current main. Easy to fix.
• https://www-issue-565.staged.apache.org/index.html#asf-plus-one - the blogs are broken. Not so easy to fix

[sebbASF]

If you want to test changes locally, please follow the instructions here:

https://github.com/apache/www-site/blob/main/README.md#local-development-and-testing