Management endpoint for Hibernate Search

[yrodiere]

Description

We could expose a management endpoint for Hibernate Search through the management interface that would allow reindexing all data, in particular.

Of course, as the endpoint would effectively give write access to indexes, it should be opt-in (enabled through a configuration flag).

Implementation ideas

I implemented something like that in a demo, see https://github.com/hibernate/hibernate-demos/pull/74/files#diff-e2ecf487e7108639ecb9c840b4fea7cca821fd31f63c48cb91ac85f608bb3765

[quarkus-bot]

/cc @gsmet (hibernate-search)