Major example update

- Increased example modularization by moving the majority
  of app logic inside dedicated modules
- Added a new `dyn_tmtc` feature for the satrs-example which is used
  to configure the heap as the backing store for TMTC packages instead
  of static stores.
- Added dedicated satrs-example chapter in satrs-book

satrs-example/src/requests.rs

@@ -22,7 +22,7 @@ pub enum Request {
 
 #[derive(Clone, Eq, PartialEq, Debug, new)]
 pub struct TargetedRequest {
-    pub(crate) target_id: TargetIdWithApid,
+    pub(crate) target_id_with_apid: TargetIdWithApid,
     pub(crate) request: Request,
 }