Remove explicit ExamineIndexRebuilder service registration and make class internal

[ronaldbarendse]

Prerequisites

• I have added steps to test this contribution in the description below

Description

Deploy uses Suspendable.ExamineEvents.ResumeIndexers(...) to resume suspended indexing after deployments, but this method still required the obsoleted ExamineIndexRebuilder type. I've updated this overload to accept the IIndexRebuilder instead and also obsoleted the unused Suspendable.PageCacheRefresher (if used, it would call ContentCacheRefresher.RefreshAll() that throws a NotSupportedException, so I've also made it a no-op call).

As per obsoletion messages and comments, I've removed the explicit ExamineIndexRebuilder service registration and make the class internal (so the IIndexRebuilder interface needs to be used/injected instead).

Testing can be done by simply checking whether all tests still succeed and optionally manually rebuilding the indexes from the backoffice and testing the search functionality.

[ronaldbarendse]

@Zeegaan If this can't be merged into 15.0.0-rc4 anymore, maybe only commit b2e38fd can be cherry-picked to the final 15.0.0 version (suggested by Bjarke)? This would remove the need for Deploy to inject the obsoleted ExamineIndexRebuilder type to be able to resume the indexers and use the interface instead...

[Zeegaan]

@ronaldbarendse it's cherry picked, thank you 🙌
I think the rest should go in v16 😁