Start(): Merge dependent path dimensions ("*_depends")

Hi @aho,

I was wondering if there's any way to merge or remove dependent dimensions when using *_depends if neither is an inner dimension and *_across and merge_across_dims cannot be used.

For example:

library(startR)

# Define the path
path <- "/esarchive/exp/ecmwf/system5c3s/monthly_mean/$var$_$var_freq$/$var$_$sdate$.nc"
sdate <- "20220101"
var <- c("tas", "prlr")
# Define dependent dimension var_freq
var_freq <- list(tas = "f6h", prlr = "s0-24h")

# Load data
data <- Start(dat = path,
              var = var,
              sdate = sdate,
              var_freq = var_freq,
              var_freq_depends = "var",
              time = "all",
              lat = indices(1:5),
              lon = indices(1:5),
              ensemble = "all",
              return_vars = list(time = "sdate"),
              retrieve = TRUE)

## var_freq is now in the data dimensions and in the metadata. I would like to not have it.
dim(data)
#     dat       var file_date  var_freq      time       lat       lon  ensemble 
#       1         2         1         1         8         5         5        51

Thanks,

Victòria