rendermode: image / single tile layer prop for print

[Grammostola]

Is your feature request related to a problem? Please describe.
If a tiled image layer like WMS or AGS_TILE is used in Origo it can look okay in the map and yield a pleasant experience when zooming and panning (sometimes in contrast to renderMode:image) however if containing labels it can get quite busy when printed because the layer is still tiled in the print preview. (This is in contrast to how Geoserver's mapfish operates by default)

(The orange area is most assuredly V Gotlandshavet)

Describe the solution you'd like
A layer property indicating whether the print control should preview the layer as a single tile ((AGS_MAP, renderMode: image),(renderMode: image))

Describe alternatives you've considered
None so far

Additional context

• We noticed it just recently on a WMS background map and road labels being repeated quite excessively
• renderMode: image makes layers blink out of and into existence which is a tad jarring but I think it preferrable to map prints with excessive labels