[services] Tunnelbroker - Database function that removes messages by a batch using messageIDs and receiver DeviceID.

Summary:
We need effectively remove messages in a batch from the DynamoDB database using a composite key (messageID + toDeviceID). For this task, we can use the inner BatchWriteItem function from ENG-1302 and delete items by batches instead of 1 by 1.

Linear task: ENG-1361

Test Plan: Run test introduced in D4478

Reviewers: karol, tomek

Reviewed By: karol, tomek

Subscribers: ashoat, tomek, adrian, atul, karol, abosh

Differential Revision: https://phab.comm.dev/D4476