Add Parameter to not Return Index Name Lists in GET Snapshots API

[original-brownbear]

The GET snapshots API currently returns the full list of all indices in a snapshot for each snapshot, regardless of the verbose setting.
This causes unmanageable response sizes in larger clusters and forces iterating through snapshots in small chunks if one wants to inspect a larger number of snapshots. E.g. a 50k indices cluster will see a million strings returned for just the index names with a common repository size of 200 snapshots.

I'll add a parameter to hide the indices list here to make the API more useful and less resource intensive to use for larger clusters.

relates #77466

[elasticmachine]

Pinging @elastic/es-distributed (Team:Distributed)