Allow to query larger tiles than the default max size with stepWidth/…

[mhugent]

QgsWMSCapabilities has mMaxWidth/mMaxHeight as the server width/height limit and mStepWidth/mStepHeight as raster size to iterate the layer. After commit 2078ef5#diff-d88af508cce11c2b59f0ad9c1ddb29824f7cce111807af3289eec2663930e39e , it is not possible anymore to make GetMap-Requests with step sizes larger than the default maximum tile size (2000x2000). This PR makes a small change to take the step width as size limit if there is no size limit set.

[github-actions]

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[agiudiceandrea]

Is the description of the "Request step size" parameter at https://docs.qgis.org/3.40/en/docs/user_manual/working_with_ogc/ogc_client_support.html#loading-wms-wmts-layers enough accurate or should/could it be enhanced in order to better clarify the exact behaviour?

[mhugent]

Is the description of the "Request step size" parameter at https://docs.qgis.org/3.40/en/docs/user_manual/working_with_ogc/ogc_client_support.html#loading-wms-wmts-layers enough accurate or should/could it be enhanced in order to better clarify the exact behaviour?

I think the description is accurate enough

[jeroenstijven]

@mhugent, @elpaso , are you and other people from the QGIS community doing all the communication in github, or also at "Element" communication application?
Because i am working on a new project for more data security with gps and blockchain.