Add surface=laterite to the surface preset

[etienne.julien@…]

surface=laterite was approved via OSM's proposal process (​Proposal:Surface=laterite, 29-0-0) and is documented at ​Tag:surface=laterite.

The built-in surface combo (chunk surface in defaultpresets.xml, shared across all highway presets) doesn't have an entry for it:

<chunk id="surface">
    <combo key="surface" text="Surface" values="paved,unpaved,asphalt,concrete,concrete:plates,concrete:lanes,paving_stones,sett,cobblestone,unhewn_cobblestone,grass_paver,compacted,fine_gravel,gravel,pebblestone,ground,mud,rock,sand,grass,wood,metal,stone,woodchips" />
</chunk>

Requesting laterite be added to that values list, labelled "Laterite".

[Famlam]

It should also be added here: https://josm.openstreetmap.de/browser/josm/trunk/resources/data/validator/combinations.mapcss#L5