UPDATE: Adds 56 functions in the Statistical section

Uses statrs for numerical functions

REFACTOR: Put statistical functions on its own module

This might seem counter-intuitive but the wasm build after this refactor
is 1528 bytes smaller :)

base/src/functions/statistical/standardize.rs

@@ -0,0 +1,38 @@
+use crate::expressions::types::CellReferenceIndex;
+use crate::{
+    calc_result::CalcResult, expressions::parser::Node, expressions::token::Error, model::Model,
+};
+
+impl Model {
+    pub(crate) fn fn_standardize(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        // STANDARDIZE(x, mean, standard_dev)
+        if args.len() != 3 {
+            return CalcResult::new_args_number_error(cell);
+        }
+
+        let x = match self.get_number_no_bools(&args[0], cell) {
+            Ok(f) => f,
+            Err(e) => return e,
+        };
+        let mean = match self.get_number_no_bools(&args[1], cell) {
+            Ok(f) => f,
+            Err(e) => return e,
+        };
+        let std_dev = match self.get_number_no_bools(&args[2], cell) {
+            Ok(f) => f,
+            Err(e) => return e,
+        };
+
+        if std_dev <= 0.0 {
+            return CalcResult::Error {
+                error: Error::NUM,
+                origin: cell,
+                message: "standard_dev must be > 0 in STANDARDIZE".to_string(),
+            };
+        }
+
+        let z = (x - mean) / std_dev;
+
+        CalcResult::Number(z)
+    }
+}