restructure the crate

- Add new shared subcrate satrs-shared to split off some shared
  components not expected to change very often.
- Renmame `satrs-core` to `satrs`. It is expected that sat-rs will remain
  the primary crate, so the core information is superfluous, and core also
  implies stability, which will not be the case for some time.

satrs-shared/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+name = "satrs-shared"
+description = "Components shared by multiple sat-rs crates"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+
+[dependencies.serde]
+version = "1"
+default-features = false
+optional = true
+
+[dependencies.spacepackets]
+version = "0.9.0"
+default-features = false
+
+[features]
+serde = ["dep:serde", "spacepackets/serde"]

satrs-shared/src/lib.rs

@@ -0,0 +1 @@
+pub mod res_code;

satrs-shared/src/res_code.rs

@@ -0,0 +1,60 @@
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
+use spacepackets::ecss::{EcssEnumU16, EcssEnumeration};
+use spacepackets::util::UnsignedEnum;
+use spacepackets::ByteConversionError;
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub struct ResultU16 {
+    group_id: u8,
+    unique_id: u8,
+}
+
+impl ResultU16 {
+    pub const fn const_new(group_id: u8, unique_id: u8) -> Self {
+        Self {
+            group_id,
+            unique_id,
+        }
+    }
+    pub fn raw(&self) -> u16 {
+        ((self.group_id as u16) << 8) | self.unique_id as u16
+    }
+    pub fn group_id(&self) -> u8 {
+        self.group_id
+    }
+    pub fn unique_id(&self) -> u8 {
+        self.unique_id
+    }
+}
+
+impl From<ResultU16> for EcssEnumU16 {
+    fn from(v: ResultU16) -> Self {
+        EcssEnumU16::new(v.raw())
+    }
+}
+
+impl UnsignedEnum for ResultU16 {
+    fn size(&self) -> usize {
+        core::mem::size_of::<u16>()
+    }
+
+    fn write_to_be_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError> {
+        if buf.len() < 2 {
+            return Err(ByteConversionError::ToSliceTooSmall {
+                found: buf.len(),
+                expected: 2,
+            });
+        }
+        buf[0] = self.group_id;
+        buf[1] = self.unique_id;
+        Ok(self.size())
+    }
+}
+
+impl EcssEnumeration for ResultU16 {
+    fn pfc(&self) -> u8 {
+        16
+    }
+}