### Description
Tracking issue: https://github.com/wormhole-foundation/wormhole-explorer/issues/535.
This pull request fixes an inconsistency between the endpoints `GET /api/v1/x-chain-activity` and `GET /api/v1/top-chain-pairs-by-num-transfers`.
The inconsistency arose because the endpoints computed the data in slightly different ways.
It was resolved by modifying the `GET /api/v1/top-chain-pairs-by-num-transfers` endpoint to use the same data source as `GET /api/v1/x-chain-activity`.
* Replace start_time and end_time query parameters with fixed ranges at the endpoint of the chain activity
Add InfluxDB tasks for enpdoint chain-activity for each timeSpan
Add cache for chain-activity endpoint
* Code review updates
ftocal
agodnic