This function can be used for simultaneous calculating of multiple `aggr_func*` functions
that accept range vector. For example, `aggr_over_time(("min_over_time", "max_over_time"), m[d])`
would calculate `min_over_time` and `max_over_time` for `m[d]`.
The full list of functions added:
- `topk_min(k, q)` - returns top K time series with the max minimums on the given time range
- `topk_max(k, q)` - returns top K time series with the max maximums on the given time range
- `topk_avg(k, q)` - returns top K time series with the max averages on the given time range
- `topk_median(k, q)` - returns top K time series with the max medians on the given time range
- `bottomk_min(k, q)` - returns bottom K time series with the min minimums on the given time range
- `bottomk_max(k, q)` - returns bottom K time series with the min maximums on the given time range
- `bottomk_avg(k, q)` - returns bottom K time series with the min averages on the given time range
- `bottomk_median(k, q)` - returns bottom K time series with the min medians on the given time range
