Consider moving main logic of rate limiter into ZetaClient

[lumtis]

Describe the Issue
Would depend on #2082
-> Once we have broken down the query into pure methods, moving the rate limiter logic will be trivial

This task is about moving the main logic of the rate limiter (algorithm for CCTX filtering) into the ZetaClient so eventual upgrade/bug of the functionality would be easier to ship/patch

Two tasks:

• Implement the right query for the crosschain module for the ZetaClient to query CCTXs with performance
• Move the filtering logic to ZetaClient