feature(mobile): hash assets & sync via checksum (#2592)

* compare different sha1 implementations

* remove openssl sha1

* sync via checksum

* hash assets in batches

* hash in background, show spinner in tab

* undo tmp changes

* migrate by clearing assets

* ignore duplicate assets

* error handling

* trigger sync/merge after download and update view

* review feedback improvements

* hash in background isolate on iOS

* rework linking assets with existing from DB

* fine-grained errors on unique index violation

* hash lenth validation

* revert compute in background on iOS

* ignore duplicate assets on device

* fix bug with batching based on accumulated size

---------

Co-authored-by: Fynn Petersen-Frey <zoodyy@users.noreply.github.com>

mobile/test/asset_grid_data_structure_test.dart

@@ -13,8 +13,8 @@ void main() {
 
     testAssets.add(
       Asset(
+        checksum: "",
         localId: '$i',
-        deviceId: 1,
         ownerId: 1,
         fileCreatedAt: date,
         fileModifiedAt: date,
@@ -23,7 +23,6 @@ void main() {
         type: AssetType.image,
         fileName: '',
         isFavorite: false,
-        isLocal: false,
         isArchived: false,
       ),
     );