Bootstrap: Add 'new' & 'updated' badges to docs to show what's changed

[sts-ryan-holton]

I thought it would be a good idea to add a small badge next to the docs navigation, next to each component/utility etc to show what's new and what's been updated with each new version of Bootstrap starting with 4.2

I think this will help people find new and updated features at a glance, the idea being that these badges could stay around until the next iteration (new major & minor releases).

e.g:

[MartijnCuppens]

I think the release notes fully cover this? And I think it would be hard to determine whether or not an item needs the badge if something is updated.

[sts-ryan-holton]

@MartijnCuppens The release notes absolutely would cover new changes, I was just thinking for those who don't really look at the release notes/Github, but rather just want to quickly see what's new with a visual indicator (a badge next to the component), maybe instead of two types, consider just having a NEW badge for new features, or if a component has extra modifier classes, consider then adding an UPDATED badge?

[andresgalante]

I really like this if there a way to automate it. If we have to manually maintain this, I'd say it's not worth it.

[XhmikosR]

We could automate it, not sure if it's worth the trouble though.

Anyway, if anyone wants to submit a simple solution, glad to review it.

[mdo]

Per last comments, could be cool, but currently not on our radar given the release notes and more.