Add retry logic to tx indexer calls

[jgryffindor]

Is your feature request related to a problem? Please describe.

Add retry logic to transaction history requests to the indexer to catch cases where the indexer is malfunctioning or local scheme caches are different on secondary nodes.

Describe the solution you'd like

Add the fix you described to retry on failures 503 with backoff

userQuery for indexer calls

Describe alternatives you've considered

Cloudflare origin pools - not ideal to create a backend pool for each endpoint to handle failures

[hansl]

I don't know how to test this, @jgryffindor. If you could help me test it, that'd be great. Right now if I just drop 99% of requests (in Chrome's network devtools) it will retry automatically. It might not respond the same with status 503.

Please advise.