[EPIC]: alerting on block ranges

As an instrument scientist I would like to be able to set up my own customized alerts for blocks being out of range.

Note: Some of the server logic for this may have been implemented in https://github.com/ISISComputingGroup/IBEX/issues/3949 , although that ticket is not fully complete at the time of writing.

This ticket is to provide an interface in the GUI, probably similar to the existing run control interface, so that scientists can configure this themselves without needing to do manual `caput` commands from a terminal. We should also consider whether, like run control, these settings can be set both as part of the configuration and then temporarily overridden.

Requested by MERLIN specifically as they want to be able to configure the alert of their collimator without needing to ask us to reconfigure nagios. It was, apparently, also a feature of SECI.

See also https://github.com/ISISComputingGroup/IBEX/issues/3811

## EPICS FOR

- [x] genie_python: https://github.com/ISISComputingGroup/IBEX/issues/5491
- [ ] GUI override: https://github.com/ISISComputingGroup/IBEX/issues/5492
- [ ] in config: https://github.com/ISISComputingGroup/IBEX/issues/5493

## Acceptance
* GUI to be able to set alert ranges
* Alert ranges can be changed via genie_python
* There are sufficient tests on the functionality
* There is sufficient documentation for the functionality