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/chemist.svg

@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Created with Inkscape (http://www.inkscape.org/) -->
+
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   version="1.1"
+   width="14"
+   height="14"
+   viewBox="0 0 14 14"
+   id="svg2">
+  <defs
+     id="defs3053" />
+  <metadata
+     id="metadata8">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title></dc:title>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <rect
+     width="14"
+     height="14"
+     x="0"
+     y="0"
+     id="canvas"
+     style="fill:none;stroke:none;visibility:hidden" />
+  <path
+     d="m 13.515914,13 c 0,-12 0.02345,-10.0477231 0.02345,-12 0,-1 -0.0469,-1 -1.539364,-1 l 0,13.038526 C 12.048052,14.003111 12.000001,14 12.718594,14 c 0.765494,0 0.79732,0 0.79732,-1 z M 2.5075377,11.624791 c 1.9893914,0.633166 3.1278615,0.633166 5.0938024,-0.07035 L 7,4 C 5,4.281407 5,4.3048576 3,4 z M 4.319933,0 5.718593,0 6.2730319,3 c -1,0.3048576 -1.5544389,0.3048576 -2.5544389,0 z m -2.2964824,14 0.2345058,-1 5.4991626,0 0.2579562,1 z m 7.4606365,-14 1.9597989,0 0,0.6097152 -1.9597989,0 z m 0,1 1.9597989,0 0,0.6097152 -1.9597989,0 z m 0,1 1.9597989,0 0,0.6097152 -1.9597989,0 z m 0,1 1.9597989,0 0,0.6097152 -1.9597989,0 z m 0,1 1.9597989,0 0,0.6097152 -1.9597989,0 z"
+     id="path2988"
+     style="fill:#ac39ac;fill-opacity:1;fill-rule:evenodd;stroke:none" />
+</svg>