refactor: move firmware workspace under firmware

firmware/boards/geprc-f722-v2/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+name = "kaptan-geprc-f722-v2"
+edition.workspace = true
+license.workspace = true
+rust-version.workspace = true
+version.workspace = true
+build = "build.rs"
+
+[lints]
+workspace = true
+
+[dependencies]
+kaptan-board = { path = "../../libs/kaptan-board" }
+platform-stm32f7 = { path = "../../platforms/stm32f7" }
+
+[[bin]]
+name = "kaptan-geprc-f722-v2"
+path = "src/main.rs"
+test = false
+bench = false