Added high-level abstraction for some PUS services

Introduced high-level abstractions for targetable requests in general.

- PUS Service 3 (HK) abstraction for targetable HK requests
- PUS Service 8 (Action) abstraction for targetable action requests

satrs/src/queue.rs

@@ -0,0 +1,49 @@
+use core::fmt::{Display, Formatter};
+#[cfg(feature = "std")]
+use std::error::Error;
+
+/// Generic error type for sending something via a message queue.
+#[derive(Debug, Copy, Clone)]
+pub enum GenericSendError {
+    RxDisconnected,
+    QueueFull(Option<u32>),
+}
+
+impl Display for GenericSendError {
+    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
+        match self {
+            GenericSendError::RxDisconnected => {
+                write!(f, "rx side has disconnected")
+            }
+            GenericSendError::QueueFull(max_cap) => {
+                write!(f, "queue with max capacity of {max_cap:?} is full")
+            }
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+impl Error for GenericSendError {}
+
+/// Generic error type for sending something via a message queue.
+#[derive(Debug, Copy, Clone)]
+pub enum GenericRecvError {
+    Empty,
+    TxDisconnected,
+}
+
+impl Display for GenericRecvError {
+    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
+        match self {
+            Self::TxDisconnected => {
+                write!(f, "tx side has disconnected")
+            }
+            Self::Empty => {
+                write!(f, "nothing to receive")
+            }
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+impl Error for GenericRecvError {}