Adds to the environment of each site a deviation that follows an
independent first-order autoregressive process with lag-one
autocorrelation rho and stationary standard deviation sd, starting from
its stationary distribution. This is a simple generator of temporal
autocorrelation, not the one used by Thompson et al. (2020).
Value
Matrix with one row per site and one column per time step, for the
env_time argument of simulate_metacommunity().

