Add self-hosted runner

[BradyPlanden]

Feature description

Add the Battery Intelligence Lab's Apple M2 runner to PyBOP's CI for benchmarking and ARM validation.

Motivation

As we expand PyBOP's estimation and optimisation methods, having a stable runner for benchmarking will provide a robust solution for new-users to compare and select methods.

Possible implementation

The final solution should be somwhat similar to: https://github.com/pybamm-team/pybamm-bench with a similar representation deployed like: https://pybamm-team.github.io/pybamm-bench/

Additional context

No response

[BradyPlanden]

To close this issue, we will need to add a few daily workflows such as unit & integration or benchmarks for the self-hosted runner to complete. It's best to not have it deployed on every push.