Move deprecated migration guides to deprecated folder

Author: datdenkikniet

book/en/src/migration.md renamed to book/en/deprecated/migration.md

@@ -23,11 +23,12 @@
     <!-- - [`#[cfg(..)]` support](./by-example/tips.md) -->
 - [RTIC vs. the world](./rtic_vs.md)
 - [Awesome RTIC examples](./awesome_rtic.md)
-<!-- - [Migration Guides](./migration.md)
-  - [v1.0.x to v2.0.0](./migration/migration_v2.md)
-  - [v0.5.x to v1.0.x](./migration/migration_v5.md)
-  - [v0.4.x to v0.5.x](./migration/migration_v4.md)
-  - [RTFM to RTIC](./migration/migration_rtic.md) -->
+- [Migrating from v1.0.x to v2.0.0](./migration_v1_v2.md)
+  - [Rust Nightly & features](./migration_v1_v2/nightly.md)
+  - [Migrating to `rtic-monotonics`](./migration_v1_v2/monotonics.md)
+  - [Software tasks must now be `async`](./migration_v1_v2/async_tasks.md)
+  - [Using and understanding `rtic-sync`](./migration_v1_v2/rtic-sync.md)
+  - [A code example on migration](./migration_v1_v2/complete_example.md)
 - [Under the hood](./internals.md)
   - [Cortex-M architectures](./internals/targets.md)
   <!--- [Interrupt configuration](./internals/interrupt-configuration.md)-->
@@ -44,13 +45,4 @@
     - [Message passing & `capacity`](./by-example/message_passing.md)
     - [Task priorities](./by-example/app_priorities.md)
     - [Monotonic & `spawn_{at/after}`](./by-example/monotonic.md) 
-  -->
-
----
-
-- [Migrating from v1.0.x to v2.0.0](./migration/migration_v2.md)
-  - [Rust Nightly & features](./migration/migration_v2/nightly.md)
-  - [Migrating to `rtic-monotonics`](./migration/migration_v2/monotonics.md)
-  - [Software tasks must now be `async`](./migration/migration_v2/async_tasks.md)
-  - [Using and understanding `rtic-sync`](./migration/migration_v2/rtic-sync.md)
-  - [A code example on migration](./migration/migration_v2/complete_example.md)
+  -->

book/en/src/migration/migration_rtic.md renamed to book/en/deprecated/migration/migration_rtic.md

@@ -87,7 +87,7 @@ mod app {
 # V2.0.0
 
 ``` rust
-{{ #include ../../../../../examples/stm32f3_blinky/src/main.rs }}
+{{ #include ../../../../examples/stm32f3_blinky/src/main.rs }}
 ```
 
 ## A diff between the two projects