Refactor trace to events to prevent redundant calculations

[Modularius]

Summary of changes

Refactors trace-to-events to allow particular settings and objects used in the algorithms to be persisted across digitiser message.

• This prevents some unnecessary memory allocations.
• Avoids redundant recalculations (e.g. recomputing the gaussian kernel each time).
• Reserves memory and objects on a per-channel basis, so that channel traces can be processed in parallel without race conditions.
• Does not persist trace data, ensuring each channel trace is still independent.
• Improves consistency in the times taken to process messages.

Note that, optimisations to the Smoothing Algorithm will be addressed in a future PR.

Instruction for review/testing

General code review.
Has been tested with simulated data.