Make layout grids work for Atlases

[ioalexei]

Test out how to get grids to work well on an atlas.

• Should hvae options to apply settings to a new atlas (as well as a standard layout)
• Possible to have different settings for different atlas pages? and/or apply to all pages?

[ioalexei]

Received a query about whether this could work for QGIS Reports as well - look into this