[DOCS] Add C to Rust code migration guide (#1629)

* docs: Add c-to-migration guide docs

* docs: Update suggested typos in `docs/Rust_migration_guide.md`

Co-authored-by: Punit Lodha <[email protected]>

---------

Co-authored-by: Punit Lodha <[email protected]>

docs/Rust_migration_guide.md

@@ -0,0 +1,71 @@
+# C to Rust Migration Guide
+
+## Porting C Functions to Rust
+
+This guide outlines the process of migrating C functions to Rust while maintaining compatibility with existing C code.
+
+### Step 1: Identify the C Function
+
+First, identify the C function you want to port. For example, let's consider a function named `net_send_cc()` in a file called `networking.c`:
+
+```c
+void net_send_cc() {
+    // Some C code
+}
+```
+
+### Step 2: Create a Pure Rust Equivalent
+
+Write an equivalent function in pure Rust within the `lib_ccxr` module:
+
+```rust
+fn net_send_cc() {
+    // Rust equivalent code to `net_send_cc` function in `networking.c`
+}
+```
+
+### Step 3: Create a C-Compatible Rust Function
+
+In the `libccxr_exports` module, create a new function that will be callable from C:
+
+```rust
+#[no_mangle]
+pub extern "C" fn ccxr_net_send_cc() {
+    net_send_cc() // Call the pure Rust function
+}
+```
+
+### Step 4: Declare the Rust Function in C
+
+In the original C file (`networking.c`), declare the Rust function as an external function:
+
+```rust
+extern void ccxr_net_send_cc();
+```
+
+### Step 5: Modify the Original C Function
+
+Update the original C function to use the Rust implementation when available:
+
+```c
+void net_send_cc() {
+    #ifndef DISABLE_RUST
+        return ccxr_net_send_cc(); // Use the Rust implementation
+    #else
+        // Original C code
+    #endif
+}
+```
+
+## Rust module system
+
+- `lib_ccxr` crate -> **The Idiomatic Rust layer**
+
+  - Path: `src/rust/lib_ccxr`
+  - This layer will contain the migrated idiomatic Rust. It will have complete documentation and tests.
+
+- `libccxr_exports` module -> **The C-like Rust layer**
+
+  - Path: `src/rust/src/libccxr_exports`
+  - This layer will have function names the same as defined in C but with the prefix `ccxr_`. These are the functions defined in the `lib_ccx` crate under appropriate modules. And these functions will be provided to the C library.
+  - Ex: `extern "C" fn ccxr_<function_name>(<args>) {}`