[Cloudflare Logpush] Add support for new fields and Page Shield data stream

[chemamartinez]

Cloudflare has updated most of their event datasets with new fields that the integration doesn't support. Here there is a table with the fields that are missed so far.

Data stream	Fields
dns_firewall	ResponseReason
firewall	LeakedCredentialCheckResult Ref
gateway_dns	CustomResolveDurationMs CustomResolverAddress CustomResolverPolicyID CustomResolverPolicyName CustomResolverResponse IsResponseCached MatchedIndicatorFeedIDs MatchedIndicatorFeedNames QueryIndicatorFeedIDs QueryIndicatorFeedNames
gateway_http	DownloadMatchedDlpProfileEntries DownloadMatchedDlpProfiles SessionID UploadMatchedDlpProfileEntries UploadMatchedDlpProfiles
gateway_network	DetectedProtocol
http_request	CacheReserveUsed ClientRegionCode ContentScanObjResults ContentScanObjTypes JA3Hash LeakedCredentialCheckResult RequestHeaders ResponseHeaders WorkerWallTimeUs
network_analytics	AttackVector ColoCity ColoCode DestinationASNName RuleName SourceASNName
network_session	DetectedProtocol
workers_trace	Entrypoint ScriptVersion

Reference: https://developers.cloudflare.com/logs/reference/log-fields/

On the other hand, a new dataset called Page Shield has been added.

[elasticmachine]

Pinging @elastic/security-service-integrations (Team:Security-Service Integrations)