Fix indexing, upgrade MeiliSearch sdk (#100)

* Hotfixes for indexing

* Handles missing INDEX_CACHE_PATH environment variable
* Exits on startup if environment variables are missing. The flag
  --allow-missing-vars disables this, but that is generally a bad
  idea, since most environment variables are required (and the ones
  that aren't should be marked as such).
* Disables the query loggers

* Upgrade meilisearch-sdk to 0.4.0 for MeiliSearch 0.16 support

* Fix swap of Forge and Fabric labeling

src/search/indexing/local_import.rs

@@ -112,7 +112,6 @@ pub async fn index_local(pool: PgPool) -> Result<Vec<UploadSearchMod>, IndexingE
                 modified_timestamp: mod_data.updated.timestamp(),
                 latest_version,
                 host: Cow::Borrowed("modrinth"),
-                empty: Cow::Borrowed("{}{}{}"),
             });
         }
     }
@@ -225,6 +224,5 @@ pub async fn query_one(
         modified_timestamp: mod_data.updated.timestamp(),
         latest_version,
         host: Cow::Borrowed("modrinth"),
-        empty: Cow::Borrowed("{}{}{}"),
     })
 }