Deprecated databroker, and split bluesky-tiled-plugins into separate repo

[danielballan]

• The bluesky-tiled-plugins package is in its own repo.
• The databroker docs are pared down, to reduce maintenance cost.
• A deprecation notice, modeled closely on the text in Document project lifecycles website-beta#1, is added.

Description

This removes bluesky-tiled-plugins and associated tooling configuration.
That package now lives in its own repo rather than sharing a repo
with databroker. (Note: It has always been a separate package. That
has not changed. Only the location of the code changed.)

Also, this re-instates documentation-publishing, which has been missing.
The documentation has rotted substantially as we prioritized resources
for Tiled deployment and deployment.

I have removed all tutorials, how-to guides, and explanations, which were
overwhelmingly broken and/or offering dated advice. I have retained
the API reference and added a deprecation notice in the README, which
also appears at the top of the index page for the docs.

Motivation and Context

How Has This Been Tested?

[mrakitin]

Looks good to me.