Platoons social functionality (#91)

### Description

This implements and completes #87 (to the best of my knowledge)

### Game

Robocraft

### Please confirm

- [x] I am the legal owner or represent the owner of all work submitted
- [x] I consent to my submission being added to this FOSS project
- [ ] This PR used LLMs to generate some or all of the code changes

Reviewed-on: https://git.ngram.ca/OpenJam/rc-servers/pulls/91
Co-authored-by: NG (Graham) <ngniusness@gmail.com>
Co-committed-by: NG (Graham) <ngniusness@gmail.com>

rc_social_room/src/events/platoon_member_update.rs

@@ -0,0 +1,31 @@
+#[derive(Clone)]
+pub struct PlatoonMemberStatusUpdate {
+    pub member_public_id: String,
+    pub member_display_name: String,
+    pub member_status: crate::data::platoon::MemberStatus,
+}
+
+impl PlatoonMemberStatusUpdate {
+    pub const CODE: u8 = 18;
+
+    pub fn as_event_params<C>(&self) -> polariton::operation::ParameterTable<C> {
+        let mut params = std::collections::HashMap::with_capacity(2);
+        params.insert(1, polariton::operation::Typed::Str(self.member_public_id.clone().into()));
+        params.insert(75, polariton::operation::Typed::Str(self.member_display_name.clone().into()));
+        params.insert(3, polariton::operation::Typed::Int(self.member_status.as_u8() as i32));
+        params.into()
+    }
+}
+
+impl <C: Send + 'static> polariton_server::events::IntoEvent<C> for PlatoonMemberStatusUpdate {
+    const CHANNEL: u8 = 0;
+    const ENCRYPT: bool = true;
+    const RELIABLE: bool = true;
+
+    fn into_event(self) -> polariton::operation::Event<C> {
+        polariton::operation::Event {
+            code: Self::CODE,
+            params: self.as_event_params(),
+        }
+    }
+}