This change continues the thread naming work from #5691 and #5758, which enables more useful lock contention profiling by ensuring threads/jobs have short, stable, human-readable names (rather than being truncated/failing due to OS limits). This changes diagnostic naming only (thread names and job/load-event labels), not behavior.
Specific modifications are:
* Shortens all thread/job names used with `beast::setCurrentThreadName`, so the effective Linux thread name stays within the 15-character limit.
* Removes per-ledger sequence numbers from job/thread names to avoid long labels. This improves aggregation in lock contention profiling for short-lived job executions.
This change renames all occurrences of `namespace ripple` and `ripple::` to `namespace xrpl` and `xrpl::`, respectively, as well as the names of test suites. It also provides a script to allow developers to replicate the changes in their local branch or fork to avoid conflicts.
