SEP 52: Convert all datetime objects to be timezone aware

My goal for my system of files is for it to be durable through time. To that effect, encoding UTC offsets makes a lot of sense, especially so given that in the last five years I have lived in 6 different timezones and in the coming few years ahead I will move through many more timezones than that.

Metadata matters.

This proposal has two discrete parts:

1. Update all existing time datetime objects. This is made easier by my having already encoded location metadata in all documents.
2. Ensure all new datetime objects going forward have
   • Update document creation scripts/flows
   • Fail to build if any datetime inconsistencies are present.

The transformation is subtle but meaningful: 2023-04-30 20:52:17 becomes 2023-04-30T20:41:26+01:00.