[Ingest Manager/Cloud] Fleet: Set good settings for Fleet in Cloud

[roncohen]

When we've arrived at good defaults for 1gb, 4gb and 8gb Kibana instances we need to work with the Cloud team to ensure that good configuration is set in Cloud for the different size of Kibanas available.

For 8gb, the following seems like a reasonable configuration:

user_settings_override_yaml: |-
    xpack.ingestManager.fleet.agentConfigRollupRateLimitIntervalMs: 1000
    xpack.ingestManager.fleet.agentConfigRollupRateLimitRequestPerInterval: 3
    xpack.ingestManager.fleet.pollingRequestTimeout: 250000
    xpack.ingestManager.fleet.maxConcurrentConnections: 10

In addition, we might need to set server.socketTimeout: 265000 until #72362 comes through cc @kobelb

We still need 1gb and 4gb configs.

[elasticmachine]

Pinging @elastic/ingest-management (Team:Ingest Management)

[jen-huang]

With Fleet Server, we no longer use these settings. Closing.