Fixed bug causing combined Delete & Insert to break the local OT system

[Luna-Klatzer]

What type of change does this PR perform?

• Maintenance (Non-breaking change that updates dependencies)
• Development changes (Changes that do not add new features or fix bugs, but update the project in other ways)
• Bug fix (Non-breaking change which fixes an issue)
• Feature (Non-breaking change which adds functionality)
• Breaking change (Major bug fix or feature that would cause existing functionality not to work as expected.)

Summary

Fixed bug causing combined Delete & Insert to break the local OT system.

Closes #271

List of Changes

• Implemented new AsyncLock which allows the async locking of multiple processes requiring sequential critical sections.
• Split unified multiple-in-one operations and added sequential locked execution.
• Fixed bug of unnecessary phantom requests for the owner property of local files.
• Removed unnecessary success callback in SDSClient.sendOTrans() which does nothing.
• Added local debug logging of the file content as a way to test OT update cycles.

Does this PR create new warnings?

None.

Linked issues or PRs

• Combined Delete & Insert break the local OT system #271