Create indexing speed benchmark

[pro-wh]

Imported from https://app.clickup.com/t/8693u8cbf

During periods of high traffic (eg Illuminex), Nexus' processing speed lagged behind the block production time. We want to be able to test/measure the indexing speed so that we can make adjustments proactively to prevent future occurrences where Nexus falls behind. One way to do this would be to run Nexus in slow-sync mode over a known period of heavy traffic.

Some notes:

1. The test should run in k8s so that Nexus is colocate with the node and network latency is minimal.
2. We want to avoid putting undue stress on both the node as well as the database. We likelt want to run this on an as-needed basis, and also use a separate postgres pod.

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Comment from Mitja Trampus:

It would be useful to test fast-sync also.

I failed to fully consider what a mess this is ops-wise :/. We do need a separate DB, and for fast-sync it would be nice to have a PersistentVolume (for the cache).