Add new fields file.origin_referrer_url & file.origin_url

[AsuNa-jp]

Checklist

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PR summary

This PR adds file.origin_referrer_url and file.origin_url

To reviewers

Size of the fields The two fields added in this PR are intended to store URL. Therefore, the default field size of 1024 bytes is insufficient. As a result, we want to set ignore_above to 8k(8192) bytes, if possible.

Default Field This field will not necessarily be included in all file events. Therefore, I set it as default_field: false, but please let me know if this is incorrect.