MySQL Archive table: improvements to truncation processes

As a systems administrator, I would like to reduce the overheads involved in truncating the MySQL archive table.

### Acceptance Criteria
- [ ] There exists a script that can truncate the archive table on all instruments ([by the same process as the existing truncation script](https://github.com/ISISComputingGroup/ibex_developers_manual/wiki/Database-Troubleshooting#reducing-database-disc-space)).
- [ ] There is an agreed, and documented, process for notifying scientists of when this script will run (usually preceding a new cycle)

### Extra Information

This ticket is a result of the discussion that took place as part of #8321 .

See also: [developer wiki page](https://github.com/ISISComputingGroup/ibex_developers_manual/wiki/Data-Generation-and-Storage-on-Instrument-PCs-(NDX's)).

## How to Test
_verbose instructions for reviewer to test changes
(**Add before making a PR**)_