Put level as the first column in basin.arrow (#1971)

The iMOD timeseries plugin shows the first column by default. That is
storage. Most users want to view level first, and have to switch
manually. So this simply puts level first, such that we get:


![image](https://github.com/user-attachments/assets/92e5ae0e-a704-45fd-bf5a-09c35008f8a7)

core/src/write.jl

@@ -119,8 +119,8 @@ function basin_table(
 )::@NamedTuple{
     time::Vector{DateTime},
     node_id::Vector{Int32},
-    storage::Vector{Float64},
     level::Vector{Float64},
+    storage::Vector{Float64},
     inflow_rate::Vector{Float64},
     outflow_rate::Vector{Float64},
     storage_rate::Vector{Float64},
@@ -167,8 +167,8 @@ function basin_table(
     return (;
         time,
         node_id,
-        storage,
         level,
+        storage,
         inflow_rate,
         outflow_rate,
         storage_rate,

core/test/run_models_test.jl

@@ -45,8 +45,8 @@
             (
                 :time,
                 :node_id,
-                :storage,
                 :level,
+                :storage,
                 :inflow_rate,
                 :outflow_rate,
                 :storage_rate,

docs/reference/usage.qmd

@@ -230,8 +230,8 @@ column         | type     | unit
 -------------- | ---------| ----
 time           | DateTime | -
 node_id        | Int32    | -
-storage        | Float64  | $\text{m}^3$
 level          | Float64  | $\text{m}$
+storage        | Float64  | $\text{m}^3$
 inflow_rate    | Float64  | $\text{m}^3/\text{s}$
 outflow_rate   | Float64  | $\text{m}^3/\text{s}$
 storage_rate   | Float64  | $\text{m}^3/\text{s}$