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/test/statistical/mod.rs

@@ -0,0 +1,22 @@
+mod test_fn_avedev;
+mod test_fn_binom;
+mod test_fn_chisq;
+mod test_fn_chisq_test;
+mod test_fn_confidence;
+mod test_fn_covariance;
+mod test_fn_devsq;
+mod test_fn_expon_dist;
+mod test_fn_f;
+mod test_fn_fisher;
+mod test_fn_hyp_geom_dist;
+mod test_fn_log_norm;
+mod test_fn_norm_dist;
+mod test_fn_pearson;
+mod test_fn_phi;
+mod test_fn_poisson;
+mod test_fn_stdev;
+mod test_fn_t_dist;
+mod test_fn_t_test;
+mod test_fn_var;
+mod test_fn_weibull;
+mod test_fn_z_test;