Initial shared instances backend (#3800)

* Create base shared instance migration and initial routes

* Fix build

* Add version uploads

* Add permissions field for shared instance users

* Actually use permissions field

* Add "public" flag to shared instances that allow GETing them without authorization

* Add the ability to get and list shared instance versions

* Add the ability to delete shared instance versions

* Fix build after merge

* Secured file hosting (#3784)

* Remove Backblaze-specific file-hosting backend

* Added S3_USES_PATH_STYLE_BUCKETS

* Remove unused file_id parameter from delete_file_version

* Add support for separate public and private buckets in labrinth::file_hosting

* Rename delete_file_version to delete_file

* Add (untested) get_url_for_private_file

* Remove url field from shared instance routes

* Remove url field from shared instance routes

* Use private bucket for shared instance versions

* Make S3 environment variables fully separate between public and private buckets

* Change file host expiry for shared instances to 180 seconds

* Fix lint

* Merge shared instance migrations into a single migration

* Replace shared instance owners with Ghost instead of deleting the instance

apps/labrinth/src/util/ext.rs

@@ -1,3 +1,5 @@
+pub const MRPACK_MIME_TYPE: &str = "application/x-modrinth-modpack+zip";
+
 pub fn get_image_content_type(extension: &str) -> Option<&'static str> {
     match extension {
         "bmp" => Some("image/bmp"),
@@ -24,7 +26,7 @@ pub fn project_file_type(ext: &str) -> Option<&str> {
     match ext {
         "jar" => Some("application/java-archive"),
         "zip" | "litemod" => Some("application/zip"),
-        "mrpack" => Some("application/x-modrinth-modpack+zip"),
+        "mrpack" => Some(MRPACK_MIME_TYPE),
         _ => None,
     }
 }