ENT-2134: 1806575 - GET /owners/{owner_key}/pools is very slow

[sonalidhome]

• Added @transactional annotation to the method listPools()

[nikosmoum]

Tests are failing here because the docker registry URL hadn't been updated on this branch yet. I just pushed the fix in #2624 now, so you need to rebase this PR to get it working.

[sonalidhome]

Rebased with candlepin:candlepin-2.9-HOTFIX branch.

[Ceiu]

Do you happen to have a measure of how fast the method is before and after this change?

[sonalidhome]

I compared the snapshot of API with and without @transactional annotation. The time taken to execute with @trasactional is 79802 ms, and, for existing is 147762 ms. Applied annotation on API, the execution is getting a little faster.

[barnabycourt]

@Ceiu on my test system this took 12 minutes before the change and 17 seconds after with the customer data set.