[Qgis-community-team] Move old core plugins documentation and port it to Processing

[matteo]

Hi guys,

some old QGIS 2.x plugins have been totally ported into Processing:

* Heatmap
* Interpolation
* Zonal statistics

and are not longer available in the plugin menu. While

* Gdal Tools

have been ported into Processing but they still have their menu.

I think we have to move (and adapt of course) the docs of the first
group into the Processing documentation and remove from the plugin
index. For The heatmap there is also a nice example that it's worth to
include and don't loose.

For gdal tools I'd say to let them where they are: even if this could
seem a duplication of documents, actually they are available in 2
different places.

index of the existing documentation here:

https://docs.qgis.org/testing/en/docs/user_manual/plugins/


Ideas?

Cheers

Matteo