feat(mean_field): added dimensions, discritization, and start of eos

The full rewrite of mean_field into something maintainable is progressing. dimensions is mostly done, discritization (domain, blocks, and fields) is done, and eos is progressing quickly

src/include/serif/discretization/domain/schema/concepts.hpp

@@ -0,0 +1,8 @@
+#pragma once
+
+#include "serif/discretization/domain/schema/traits.hpp"
+
+namespace serif::discretization::domain::schema {
+    template <typename T>
+    concept IsSchema = is_schema_v<T>;
+}