[12.1.x] Remove deprecated classes/methods

[sbordet]

Jetty version(s)
12.1.x

Description
Many classes carry over deprecated methods that can be removed, for example:

EndPoint.get[Local|Remote]Address().

Review what needs to be removed before the final release of 12.1.x.

[gregw]

I think our policy on removing deprecated API should be:

• removed in any major release (e.g. 13.0.0)
• removed in a minor release (e.g. in 12.1.0), but only when it has been deprecated for at least 6 patch released e.g. if current 12.0 release is 12.0.10, it must have been deprecated in or before 12.0.4
• removed in a patch release if it was deprecated in a previous minor release, but with insufficient patch releases. e.g. if last 12.0 release was 12.0.10, then API deprecated in 12.0.8 can be removed in 12.1.3 (7th patch release).

This means that we can remove only in the next minor release, but only after 6 patch releases (approx 6 months).

[sbordet]

I have captured this policy in #12194.