Deprecate Document Templates

[jdiehl]

Please Review @arjan-h

[ConnorLand]

This PR just needs a RN added to 10.24 RNs before merge.

I added the changedate label on this PR to remind the merger to add a RN about this in 10.24 RNs. I can't stage that RN here yet, because the doc doesn't exist. Copy/paste this text please:

Document Templates were deprecated in 10.24. For information on migrating to supported methods, see Document Templates.

It's a fairly big impact bullet, but small in words. So it could go in a general RN section, or be made into its own small section for visibility. I leave that choice to whoever merges this.

[MariaShaposhnikova]

@ConnorLand , 10.24 RN are available in this PR: #9704

[MariaShaposhnikova]

@ConnorLand, the release note was already there in Deprecations, but I used your version. Please see this commit: a63c5ad

[MariaShaposhnikova]

@ConnorLand , this PR changes refguide, so the changes are for 11 GA (11 GA has the same change). Will changes be transferred to Mendix 10 as well?

[ConnorLand]

@ConnorLand , this PR changes refguide, so the changes are for 11 GA (11 GA has the same change). Will changes be transferred to Mendix 10 as well?

I have made a separate PR and am duplicating these changes for Mx10 there. #9728