Add example CLI for audit log data retrieval

[tobiscr]

Adds a Go CLI tool (retrieve-auditlog-data) to retrieve audit log records from the SAP Audit Log Service v2 API on SAP BTP.

What it does:

• Authenticates via OAuth2 client credentials (read from a local service binding file)
• Fetches /auditlog/v2/auditlogrecords with optional --time-from / --time-to filters
• Follows server-side pagination automatically and prints all records as pretty-printed JSON

How to test:

cd retrieve-auditlog-data
go test ./...
go run main.go get --time-from 2026-06-01T00:00:00 --time-to 2026-06-22T23:59:59

[cla-assistant]

All committers have signed the CLA.

[tobiscr]

thanks for the great feedback!