docs(docs): Add ADR on structured logging.

[stevenj]

Description

Adds an ADR about structured logging.

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[github-actions]

✅ Test Report | ${\color{lightgreen}Pass: 297/297}$ | ${\color{red}Fail: 0/297}$ |

[minikin]

That sounds like a good idea. Are we going to have concrete specs for this later?
For example, we said, Date and Time *MUST* always be referenced to UTC and not Local Time. But what exact format are we going to use? For example, we'd prefer ISO 8601, not RFC 1123 .

[stevenj]

That sounds like a good idea. Are we going to have concrete specs for this later? For example, we said, Date and Time *MUST* always be referenced to UTC and not Local Time. But what exact format are we going to use? For example, we'd prefer ISO 8601, not RFC 1123 .

Yes we can. The only reason I didn't is because I wasn't sure what would be easy across all the languages. For Rust we are using rfc_3339 (a subset of ISO 8601).
So we could say the time can be formatted in either ISO 8601 or RF 3339.