[Feature] More Flexibility in PAPERLESS_FILENAME_FORMAT

[kaiwei]

Hi, I'm hoping to have my filenames in a very specific way, due to legacy issues of over 10+ years of PDFs... I understand there is a semi-prescribed format which we can rearrange at will (thanks!) using the PAPERLESS_FILENAME_FORMAT but I'm trying to achieve the following:

YYYYMMDD_HHMMSS_[tag][Correspondent][Title].pdf
OR basically
20161222_124100_I1.1_BofA_Monthly_Statements.pdf

The [created] date and time format now unfortunately doesn't achieve this, e.g. I can't figure out how to get time to show up even though it's there in the file attributes. Is there someway we can achieve this? I thought of using a post-script to amend it but this changes the Generated File Name which will simply result in missing PDF files from paperless-ng.

Thanks!

Josh