PR #87647 - pkg/keys: implement SafeFormatter for `roachpb.Key`

[cockroach-teamcity]

Exalate commented:

Related PR: cockroachdb/cockroach#87647
Commit: cockroachdb/cockroach@6f93145

---

Release note (security update): redacted logs will now reveal
pretty-printed keys, except for the index key values themselves.
For example /Table/42/1222/‹x› will be shown instead of ‹x›
(which was shown previously). This improved redaction is available
for the /Table keyspace for both system and application tenants.
Other keyspaces such as /Meta1, /Meta2, /Local, etc. are not
yet supported.

Jira Issue: DOC-5715