Draft: Obsolete: Port 'Added read-timeout and write-timeout' to Kea 2.2.x (#2735, #2688)

Fixes #2735 (closed).

This ports !1887 (merged) that solves #2688 (closed) to Kea 2.2.x. This is a purely mechanical port; it only rebases the commits on top of branch v2_2 and fixes merge conflicts.

We encountered the same bug as the original reporter; with this patch in place the bug went away.