OSM OpenMapTiles style (#1420)

* OpenMapTiles style

* Rename style snippets from layer_name.json to defaultstyle.json

* Add README to icons dir.

* Add README to icons dir.

* Rename snippets to style.json

* Fix spritezero - move icons to svg subdir

* Move icons from style/icons/svg directly to style/icons

Co-authored-by: Tomas Pohanka <TomPohys@gmail.com>

style/icons/stone.svg

@@ -0,0 +1,10 @@
+<svg width="14" height="14" viewBox="0 0 14 14" fill="none" xmlns="http://www.w3.org/2000/svg">
+<g clip-path="url(#clip0)">
+<path fill-rule="evenodd" clip-rule="evenodd" d="M6.00001 2C1.57618 1.99816 6.19793e-06 3.99153 0 7.93899C6.19793e-06 11 3.00001 12 7.73828 11.9904C11.7317 11.9904 14.0163 9.57512 14 7.42361C14 5 9.00001 2 6.00001 2ZM4.00001 4H5.00001V5H4.00001V4ZM6.00001 4H9.00001V5H6.00001V4ZM2.00001 7H11V8H2.00001V7ZM4.00001 9H9.00001V10H4.00001V9Z" fill="#734A08"/>
+</g>
+<defs>
+<clipPath id="clip0">
+<rect width="14" height="14" fill="white"/>
+</clipPath>
+</defs>
+</svg>