Release Talkyard v1

Currently preparing Talkyard v1 — a major new version (a new epoch).

Installations instructions: https://github.com/debiki/talkyard-prod-one/tree/ty-prod-one-v1

Upgrade instructions: https://github.com/debiki/talkyard-prod-one/blob/ty-prod-one-v1/docs/upgrade-v0-to-v1.md
To upgrade from Talkyard v0 to v1, you install Talkyard v1 side-by-side with v0, backup v0, and restore the backup to v1.

Talkyard v1 upgrades 3rd party software, e.g. Postgres, ElasticSearch. Talkyard v0 will stop getting new features, only bug fixes.

Feedback welcome! You can post comments below.