Channels: Add role / default permission set routes.

Server: Add role create / delete route.

src/routes/servers/roles_delete.rs

@@ -0,0 +1,48 @@
+use crate::database::*;
+use crate::notifications::events::ClientboundNotification;
+use crate::util::result::{Error, Result};
+
+use mongodb::bson::doc;
+
+#[delete("/<target>/roles/<role_id>")]
+pub async fn req(user: User, target: Ref, role_id: String) -> Result<()> {
+    let target = target.fetch_server().await?;
+
+    let perm = permissions::PermissionCalculator::new(&user)
+        .with_server(&target)
+        .for_server()
+        .await?;
+
+    if !perm.get_manage_roles() {
+        Err(Error::MissingPermission)?
+    }
+
+    get_collection("servers")
+        .update_one(
+            doc! {
+                "_id": &role_id
+            },
+            doc! {
+                "$unset": {
+                    "roles.".to_owned() + &role_id: 1
+                }
+            },
+            None
+        )
+        .await
+        .map_err(|_| Error::DatabaseError {
+            operation: "update_one",
+            with: "servers"
+        })?;
+    
+    // remove role from members
+    // remove role from channels
+    
+    ClientboundNotification::ServerRoleDelete {
+        id: target.id.clone(),
+        role_id
+    }
+    .publish(target.id);
+
+    Ok(())
+}