channel projects (#8456)

Add plumbing for hosted projects. This will currently show them if they
exist
but provides no UX to create/rename/delete them.

Also changed the `ChannelId` type to not auto-cast to u64; this avoids
type
confusion if you have multiple id types.


Release Notes:

- N/A

crates/collab/src/db/tables/hosted_project.rs

@@ -0,0 +1,18 @@
+use crate::db::{ChannelId, ChannelVisibility, HostedProjectId};
+use sea_orm::entity::prelude::*;
+
+#[derive(Clone, Debug, PartialEq, Eq, DeriveEntityModel)]
+#[sea_orm(table_name = "hosted_projects")]
+pub struct Model {
+    #[sea_orm(primary_key)]
+    pub id: HostedProjectId,
+    pub channel_id: ChannelId,
+    pub name: String,
+    pub visibility: ChannelVisibility,
+    pub deleted_at: Option<DateTime>,
+}
+
+impl ActiveModelBehavior for ActiveModel {}
+
+#[derive(Copy, Clone, Debug, EnumIter, DeriveRelation)]
+pub enum Relation {}