feat-webgarages-121 (#129)

### Description

Closes #121

### Please confirm

- [x] I am the legal owner or represent the legal owner of all work submitted (including LLM-generated code, if any)
- [x] I consent to my changes being added to this FOSS project
- [x] I have confirmed that this does not add new errors or warnings with `utils/clippy.sh`
- [ ] This PR used LLMs to generate some or all of the code changes

Reviewed-on: https://git.ngram.ca/OpenJam/rc-servers/pulls/129

rc_plugins/src/lib.rs

@@ -1,6 +1,7 @@
 pub mod chat;
 pub mod vehicle_validation;
 pub mod team_selection;
+pub mod vehicle_import;
 
 pub trait Plugin: Send + Sync {
     fn self_check(&self) -> bool {

rc_plugins/src/vehicle_import/mod.rs

@@ -0,0 +1,2 @@
+mod plugin;
+pub use plugin::{VehicleImportPlugin, VehicleImportErrorCode, VehicleImportData};

rc_plugins/src/vehicle_import/plugin.rs

@@ -0,0 +1,35 @@
+#[repr(u8)]
+#[derive(Debug)]
+pub enum VehicleImportErrorCode {
+    Invalid,
+    Unsupported,
+    UnknownCube,
+}
+
+impl core::fmt::Display for VehicleImportErrorCode {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::Invalid => write!(f, "Invalid/corrupt data"),
+            Self::Unsupported => write!(f, "Unsupported/unrecognized data"),
+            Self::UnknownCube => write!(f, "Unknown cube in data"),
+        }
+    }
+}
+
+impl core::error::Error for VehicleImportErrorCode {}
+
+#[derive(Debug)]
+pub struct VehicleImportData {
+    pub cube_data: Vec<u8>,
+    pub colour_data: Vec<u8>,
+    pub vehicle_name: Option<String>,
+    pub vehicle_author: Option<String>,
+}
+
+pub trait VehicleImportPlugin: crate::Plugin {
+    //fn supports(&self) -> Vec<String>;
+    /// Preferred file extension for the raw data
+    fn file_ext(&self) -> &'static str;
+    fn import(&self, upload: &[u8]) -> Result<VehicleImportData, VehicleImportErrorCode>;
+    fn export(&self, data: &VehicleImportData) -> Result<Vec<u8>, VehicleImportErrorCode>;
+}