Apply standard date format to `timeline.time` values

[jdaigneau5]

Summary

All date fields defined in the CVE record schema are formatted to yyyy-MM-ddTHH:mm:ss.sssZ (ISO-8601, UTC) except for timeline.time values. The same format should apply to this field.

Definition of Done

• timeline.time values are formatted to yyyy-MM-ddTHH:mm:ss.sssZ (ISO-8601, UTC) in CNA and ADP containers.