[ping_directory] Add support of LDAP Access datastream

[muskan-agarwal26]

Add an ldap_access data stream to the ping_directory integration.

Collects PingDirectory LDAP access logs via UDP and logfile (filestream) inputs. Covers LDAP operations such as bind, search, connect, and disconnect.

Includes:

• UDP and filestream data collection
• Ingest pipeline with ECS mappings (source.ip, user.dn, event.action, event.outcome, event.duration)
• Field definitions, pipeline and system tests, sample event, and documentation
• Dashboard covering LDAP operations over time, operation types and outcomes, most active clients, top search filters, and failures

Part of #19103.

[infra-vault-gh-plugin-prod]

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