Add section referencing latest release notes

[jcfr]

Is your feature request related to a problem? Please describe.

Prospective users browsing on https://slicer.org can't easily learn about the latest features and improvement introduced in the different releases.

There are two aspects:

• (1) The landing page should be updated to include a section equivalent to the following one historically available on the Slicer wiki:

  

  Source: https://www.slicer.org/wiki/Documentation/4.10/Announcements

• (2) The list collection of prior announcements should easily be discoverable. This allows users, funding agencies and developers to easily lookup information associated with prior releases. For reference, information is the Slicer mediawiki was presented like this:

  

  Source: https://www.slicer.org/w/index.php?title=Documentation

Describe the solution you'd like

• For (1), I suggest to use a regular "notification" associated with the data 🎉 icon.
  See https://www.csrhymes.com/bulma-clean-theme/docs/page-components/notifications/#bulma-notifications

• For (2), I suggest to update the Release-Details to include link to announcements, release notes and acknowledgments.

Describe alternatives you've considered

• Reference to the latest release notes may be included with:
  • a "notification" either dismissible or permanent. See https://www.csrhymes.com/bulma-clean-theme/docs/page-components/notifications/#bulma-notifications
  • a "callout" section. See https://www.csrhymes.com/bulma-clean-theme/docs/page-components/callouts/#set-the-callouts-in-the-frontmatter

[jcfr]

To follow-up, we also discussed adding a dedicated "Release Notes":

[jcfr]

Originally shared by @finetjul by email:

Suggestion: adding a direct link to the release notes discourse category from the download page would inform about (and help the user decide if it's worth it to download) the new minor/major release.

More generally speaking, it would be helpful to cross reference it a bit more, e.g. here or here. I did see the Announcement top-level category at first, but did not see the Release note sub category.

[jcfr]

Originally shared by @Thibault-Pelletier by email:

[...] fan of MONAI's way of documenting the changes to their library :
https://docs.monai.io/en/stable/whatsnew.html

[...] maybe this could be done in Slicer's read the docs and pointed to on slicer.org?