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_change_sides.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="#bf0000" id="svg_1" orient="x" points="664.9855026971727,249.999995640346 633.318836030506,304.8482712133604 569.9855026971727,304.8482712133604 538.318836030506,249.999995640346 569.9855026971726,195.15172006733155 633.318836030506,195.15172006733155 664.9855026971727,249.99999564034596 " shape="regularPoly" sides="6" stroke="#0000bf" stroke-width="15"/>
+ </g>
+
+</svg>