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/storage_tank.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="M5.45117 4.78886e-05C4.17927 -0.00647447 2.92306 0.653222 2 2.00005V14H9V6.00005H11V14H12V2.00005H11V4.94145H9V2.00005C8.01068 0.679311 6.72308 0.00657025 5.45117 4.78886e-05Z" fill="#666666"/>
+</g>
+<defs>
+<clipPath id="clip0">
+<rect width="14" height="14" fill="white"/>
+</clipPath>
+</defs>
+</svg>