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__/scenario5-check tool_line_clone.svg

@@ -0,0 +1,10 @@
+<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>
+  <line fill="none" id="svg_2" opacity="0.5" stroke="#000000" stroke-width="5" x1="200" x2="450" y1="200" y2="450"/>
+  <line fill="none" id="svg_3" opacity="0.25" stroke="#000000" stroke-width="5" x1="220" x2="470" y1="220" y2="470">
+   <animate attributeName="opacity" begin="indefinite" dur="0.2" fill="freeze" id="svg_4" to="0.5"/>
+  </line>
+ </g>
+
+</svg>