Add date tag besides git hash and latest

[consideRatio]

I think the use of dates can be very helpful, because they communicate more than git hashes.

When looking at what image is used, and you see its built on a certain date, a lot of conclusions can be drawn that takes further investigation if its a git hash instead, also more info than latest.

I propose this is enabled by default and made opt-out, because there is little harm to push another tag.