Deprecate local `LRUMap`, use `jackson-databind` provided one instead

[cowtowncoder]

(note: similar to FasterXML/jackson-jaxrs-providers#178)

This repository contains an old copied/forked version of LRUMap (pre-2.12) which has not been updated unlike one in jackson-databind (which was fully re-written in 2.14). Let's get rid of forked version, use databind one.

This can be done for 2.16.1 patch, given benefits of upgrade.