[Task] Add aggregate information for active recordings in the GraphQL API

[hareetd]

In #924 the GraphQL schema for archived recordings was changed to include aggregate information alongside the actual recording list itself.

type Recordings {
    active(filter: ActiveRecordingFilterInput): [ActiveRecording!]!
    archived(filter: ArchivedRecordingFilterInput): Archived!
}

...

type Archived {
    data: [ArchivedRecording!]!
    aggregate: AggregateInfo!
}

type AggregateInfo {
    count: Long!
}

Active recordings should mirror this change for consistency purposes. Adding more aggregate information fields alongside the count for both types of recordings would be nice as well.

[andrewazores]

Related: https://github.com/cryostatio/cryostat/issues/964