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/taoist.svg

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Created with Inkscape (http://www.inkscape.org/) -->
+
+<svg
+   xmlns="http://www.w3.org/2000/svg"
+   version="1.1"
+   width="14"
+   height="14"
+   viewBox="0 0 14 14">
+  <rect
+     width="14"
+     height="14"
+     x="0"
+     y="0"
+     id="canvas"
+     style="fill:none;stroke:none;visibility:hidden" />
+  <path
+     d="m 7,14 c 3.858078,0 7,-3.169117 7,-7 C 14,3.169117 10.877274,0 7,0 3.122726,0 0,3.13993 0,7 c 0,3.860071 3.141922,7 7,7 z M 7,13 C 3.680369,13 1,10.319631 1,7 1,3.680369 3.680369,1 7,1 10,1 11,6.4793944 7,7 3,7.520606 4.084746,13 7,13 z M 7,11 C 6.447715,11 6,10.552284 6,10 6,9.447716 6.447715,9 7,9 7.552285,9 8,9.447716 8,10 8,10.552284 7.552285,11 7,11 z M 7,5 C 7.552285,5 8,4.552285 8,4 8,3.447715 7.552285,3 7,3 6.447715,3 6,3.447715 6,4 6,4.552285 6.447715,5 7,5 z"
+     id="taoist" />
+</svg>