Add transactions to the many_partitions scale test

[ballard26]

This PR extends the many_partitions test to use transactions in background traffic during a restart stress test. Not sure if this is the best place to insert transactions into our scale tests. However, I thought it'd be a good starting place for a discussion about where adding in transactions would be appropriate.

This PR requires redpanda-data/kgo-verifier#16 to be merged for the changed test to pass.

Backports Required

• none - not a bug fix
• none - issue does not exist in previous branches
• none - papercut/not impactful enough to backport
• v22.3.x
• v22.2.x
• v22.1.x

UX Changes

N/a

Release Notes

N/a

[jcsp]

It's a bit odd to pick out the restart stress portion of the test and only run that bit with transactions.

The approach for compaction is to have a top level set of repeater_kwargs, and two different test cases (compacted vs. non) -- can we do the same for transactions? Maybe rather than each feature independently, we should have just two variants of the test: vanilla (no compaction or transactions) and "fully loaded" (compaction, transactions enabled).

I think that'll be useful in identifying which failures result from issues in the primary data path, vs. which ones relate to particular optional features.

[jcsp]

Not sure where you're running this in development, but would be good to try it on i3en.6xlarge instances. The nightly runs are on i3en.xlarge for cost, but that's only ~10k partitions, the i3en.6xlarge instances will get you up to the HARD_PARTITION_LIMIT in the test.

When you try the version with+without transactions, it may be that we get an interesting result in terms of what the hard partition limit can be with transactions on vs. off.