Switched custom quantities to using a macro for generation.

generate-quantity/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "generate-quantity"
+description = "Macros for generating physical quantity type"
+version.workspace = true
+edition.workspace = true
+repository.workspace = true
+readme.workspace = true
+license.workspace = true
+
+[lib]
+proc-macro = true
+
+[dependencies.quote]
+workspace = true
+[dependencies.syn]
+workspace = true