In the index management page, add an action button to reindex
https://marvelapp.com/70fi0b1/screen/67706473

When we click the button a confirmation message is required
https://marvelapp.com/70fi0b1/screen/67706474

If the user clicks on "ok" then come back to the cache detail page.

When reindex is going on, this is visible in the Cache detail header
https://marvelapp.com/70fi0b1/screen/67706475

When the reindex is over, display a message
https://marvelapp.com/70fi0b1/screen/67706476

While reindex is going on, do not allow reindex again or purge index again
https://marvelapp.com/70fi0b1/screen/67746306