Metadata download: timestamps are serialized as unix integer timestamp rather than iso-string

[corneliusroemer]

From #1421:

submittedAt and released at is a unix timestamp, we should serialize it as human readable timestamp, something like 2023-01-05Z23:11:56?

This requires changes to SILO

[theosanderson]

dupe: #838

[theosanderson]

IMO we don't necessarily need to change SILO, we just need to ensure we have a readable version in addition.

[corneliusroemer]

Thanks for finding the dupe! We should indeed export to metadata the normal iso-date string, like 2023-01-20 - and omit the unix timestamp IMO

[theosanderson]

We use the timestamp to display the time of release on the website which was at some stage considered a desirable feature

[corneliusroemer]

-Yes this issue is about metadata export to TSV, not about seq details page.

In the TSV, it would be better to have something that isn't as plain as an integer - I feel the timestamp could be committed for the metadata export but either is fine.

[theosanderson]

👍 I thought you were saying omit from SILO export

[theosanderson]

I think the only agreed change we plan to make year has been carried out, as discussed in #838