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

packages/svgcanvas/dataStorage.js

@@ -0,0 +1,28 @@
+/** A storage solution aimed at replacing jQuerys data function.
+* Implementation Note: Elements are stored in a (WeakMap)[https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap].
+* This makes sure the data is garbage collected when the node is removed.
+*/
+const dataStorage = {
+  _storage: new WeakMap(),
+  put: function (element, key, obj) {
+    if (!this._storage.has(element)) {
+      this._storage.set(element, new Map())
+    }
+    this._storage.get(element).set(key, obj)
+  },
+  get: function (element, key) {
+    return this._storage.get(element)?.get(key)
+  },
+  has: function (element, key) {
+    return this._storage.has(element) && this._storage.get(element).has(key)
+  },
+  remove: function (element, key) {
+    const ret = this._storage.get(element).delete(key)
+    if (this._storage.get(element).size === 0) {
+      this._storage.delete(element)
+    }
+    return ret
+  }
+}
+
+export default dataStorage