[UX] Dashboard block to highlight recent and notable bug fixes or feature updates

Description of the need

Better communicate recent changes to Backdrop Core to users. Most users probably do not read the release notes very closely for update and may not read the blog post (assuming it gets published) that describes updates and changes.

Proposed solution

That we add a block on the dashboard (similar to Backdrop News) that highlights noteworthy changes to Backdrop Core, either bug fixes or new features with links to more information on Github or BackdropCMS.org.

Each notice in this "Changes" block might include:

1) Short Description 2) 1-2 Sentences regarding the importance of the change 3) Version change was made 4) Link to Github issue

Better communication of new features and bug fixes might encourage users to update their sites quicker and links to Github issues may pull some users into the issue queue that would not normally go there. Imagine a user reading a description of change to core that "Moves the location of breadcrumbs on default installs" and is interested enough to follow a link from their site to the Github issue queue discussing this change. This user learns more about:

1) How Backdrop is built 2) How to report issues in general OR issues specific to this new feature 3) How to get more involved in making feature requests and helping with Backdrop

Alternatives that have been considered

Nothing specific other than what we are already doing.

Additional information

I'm not yet sure if this is a good idea, but would love to get feedback on the idea and find out if others have other ideas to better communicate to users and site admins the changes that we are making to Backdrop Core (and potentially engage them in the process).

Draft of feature description for Press Release (1 paragraph at most)

"Beginning with this recent version of Backdrop CMS, site administrators will find up to dates notifications on their dashboard regarding recent bug fixes and changes to Backdrop core that might benefit them."