Allow changing texture mag/min filter of Heatmap vis

[axelboc]

Fix #1721

[HeatmapVis, HeatmapMesh] Add props magFilter and minFilter to allow changing the heatmap texture's magnification and minification filters (NearestFilter by default)

[loichuder]

Cool, thanks !

We will have to see if this is enough or if we should do something more fancy as @t20100 suggested in the issue.

[stufisher]

Thanks for this, ill try and check it out