The Dexterity-reference from the training and the dexterity docs should both move into docs #1298

The Dexterity-reference from the training (https://training.plone.org/mastering-plone/dexterity_reference.html) and the dexterity docs should both move into plone/documentation. I would not pull the dexterity docs in (as a submodule) but rather move it there since it is very very "core".

Sources

• https://github.com/plone/plone.app.dexterity/tree/master/docs
• https://github.com/plone/training/blob/main/docs/mastering-plone/dexterity_reference.md

Advantages

• Core docs should be in the plone/documentation, instead of scattered across multiple repositories.
• More likely to get contributions through the plone/documentation repository. No need to explain, "Oh, sorry, you have to go over to plone/plone.app.dexterity to update this one section of the docs."
• No need to deal with submodules.

Disadvantages

• Docs would not be kept together with the project.

To Dos

• Prepare for plone.app.dexterity docs #1455
• Move the plone.behavior readme into plone/documentation #1309
• Import https://github.com/plone/training/blob/main/docs/mastering-plone/dexterity_reference.md

See also

• Migrate plone.app.dexterity docs into Plone 6 Documentation #1445
• Migrate content from Training: dexterity field/widget reference #1143
• plone/content/creating.html outdated for dexterity content (folder restrictions) #707

Originally posted by @pbauer in #1290 (comment)