Past version warning is too restrictive

[Yorkemartin]

Past version warning should be configurable. The protocol I am building docs for are immutable smart contracts deployed on ethereum, so calling them "maintained" or not will confuse users. I imagine others feel similarly - such as the comment below

Would it be also possible to allow disabling or customizing the banner of past versions?

The current message hints that past versions are not maintained anymore which can be wrong. In the case of FoalTS, past versions have a lifetime during which bugs and security holes are fixed even if no new features are added.

I currently use this (hacky) workaround:

.alert.alert--warning.margin-bottom--md {
  display: none;
}

Originally posted by @LoicPoullain in #3013 (comment)

[slorber]

agree we should make this configurable (it's not for now)

duplicate of #3013