Make a single parameter perturbation file in inference

[alsnhll]

Right now, separate function for perturb_spar, perturb_hnpi, etc, can all be combined into a single file to avoid redundancy and to make it easier to edit them. Additionally, these should be updated to not read from the config each time but to read from the previously written files

[alsnhll]

Additionally, if we perturb all parameters within a single file, it will be easier to do multi-dimensional perturbations based on correlations among parameters (for example, initial condition value and R0 value might have some mutual non-identifiability and thus be highly correlated if perturbed independently, so without perturbing together would have a very low acceptance rate).