chore(crates): introduce new config crate for sprout configuration

crates/config/src/generators/matrix.rs

@@ -0,0 +1,16 @@
+use crate::entries::EntryDeclaration;
+use serde::{Deserialize, Serialize};
+use std::collections::BTreeMap;
+
+/// Matrix generator configuration.
+/// The matrix generator produces multiple entries based
+/// on input values multiplicatively.
+#[derive(Serialize, Deserialize, Debug, Default, Clone)]
+pub struct MatrixConfiguration {
+    /// The template entry to use for each generated entry.
+    #[serde(default)]
+    pub entry: EntryDeclaration,
+    /// The values to use as the input for the matrix.
+    #[serde(default)]
+    pub values: BTreeMap<String, Vec<String>>,
+}