separate svgcanvas from svgedit

now you can use directlt svgcanvas. see readme.md

* configure workspaces
* move svgcanvas to packages folder
* move utils to common and paint to svgcanvas
* make svgcanvas a dependency of svgedit
* update deps
* workspaces requires npm 7 at least so the ci needs a new node version
* update github actions to V3
* update snapshots using custom svg exports
* remove unmaintained cypress snapshot plugin
* new github action to add coverage in PR
* Update onpushandpullrequest.yml
* svgcanvas v7.1.6

cypress/__svgSnapshots__/scenario6-check tool_polygon_delete.svg

@@ -0,0 +1,7 @@
+<svg width="640" height="480" xmlns="http://www.w3.org/2000/svg" xmlns:svg="http://www.w3.org/2000/svg">
+ <g class="layer">
+  <title>Layer 1</title>
+  <polygon cx="325" cy="250" edge="63.33" fill="#FF0000" id="svg_1" orient="x" points="378.87455119562924,250 341.6481518837726,301.23774297708 281.41457251841285,281.6666666666667 281.4145725184128,218.33333333333334 341.6481518837726,198.76225702291998 378.87455119562924,250 " shape="regularPoly" sides="5" stroke="#000000" stroke-width="5"/>
+ </g>
+
+</svg>