Make init g dependency of run_parameters explicit

• Make run_parameters dependence on init_g explicit

• Remove call to init_init_g from fields as this dependency now handled by init system.

Run parameters initialisation may need to know about the restart state etc. so we need to make sure we call init_init_g before init_run_parameters. This wasn’t explicit in the code or the init chain. This change just makes this explicit in the init chain and removes calls in fields which were attempting to enforce this order.