setup_sim: Set-up simulation
In mrajeev08/simrabid: Individual-based model of canine rabies

setup_sim takes inputs and generates all needed outputs to be passed to simrabid.

setup_sim(
  start_date = "2002-01-01",
  apprx_end_date = "2020-01-01",
  days_in_step = 7,
  rast,
  death_rate_annual,
  birth_rate_annual,
  waning_rate_annual,
  block_fun = block_cells,
  params = list(start_pop),
  by_admin = FALSE
)

`start_date`	date, the starting date for the simulation in year-month-day format
`apprx_end_date`	date, the approximate end date for the simulation in year-month-day format, the set-up fun will return the actual end date of the simulation rounded up to the maximum number of timesteps in the interval based on `days_in_step`
`days_in_step`	the number of days to aggregate timesteps by, defaults to 7 ("weekly"), but can be arbitrary number of days
`rast`	raster, from `setup_space` the output raster with each cell allocated to a location
`death_rate_annual`	annual death rate, either length 1 or length of the admin units
`birth_rate_annual`	annual birth rate, either length 1 or length of the admin units
`waning_rate_annual`	annual waning rate of vaccination immunity, either length 1 or length of the admin units
`block_fun`	a function that designates the indices to track/block/consider out-of-bounds (see `block_cells` for an example)
`params`	additional params to pass, must include start_pop, a numeric vector of the starting population in each grid cell of `rast`
`by_admin`	logical, should mixing be at the admin (or arbitrary) scale?