Add in a new option for CMIP7 1850 Ozone

There is new preliminary CMIP7 dataset for Ozone that we should bring in. Similar to other similar issues I suggest adding

clim_cmip7_1850

option to DATM_PRESO3

How this was done in CAM:

&prescribed_ozone_nl
prescribed_ozone_cycle_yr = 1850
prescribed_ozone_datapath = '/glade/derecho/scratch/tilmes/archive/b.e30_alpha07c_cesm.B1850C_MTt4s.ne30_t232_wgx3.251.001/atm/proc/ozone_strataero_day_5'
prescribed_ozone_file = 'ozone_strataero_b.e30_alpha07c_cesm.B1850C_MTt4s.ne30_t232_wgx3.251.001_1850climo_zm_5day_c251204.nc'
prescribed_ozone_name = 'O3'
prescribed_ozone_type = 'CYCLICAL'

See:

https://github.com/NCAR/cesm_dev/issues/264