Muon lifetime fitting

A bit like https://github.com/ISISComputingGroup/ibex_bluesky_core/issues/227 (do after 227 has been implemented). In many ways this is a simpler version of that spin-asymmetry ticket.

## Description

- In a `SimpleDae` reducer:
- Measure spectra from $N$ detectors - so you have $N$ different arrays of counts vs time
- Sum the $N$ detectors together - so you have a single array of counts vs time
- Normalize by good frames - so you have a single array of normalized counts vs time
- Fit with $\huge c = N_0 e^{-\lambda_0 t} + N_1 e^{-\lambda_1 t}$
* Scientists will provide initial guesses for all fit parameters
- From the reducer return the fit parameters
- The outer fit might be either a peak-like, a Gaussian, a momentum scan fit, or erf/erfc. Therefore you can assume that our existing fitting models are already suitable, for fits at this level.

### Acceptance criteria
- [ ] Algorithm in description is implemented.

Discussed 00:27:00 - in planning 02/10/25