Merged PR 162: Implement symbols and other stuff (see desc)

Implement symbols
- Add, Remove, Select Container
- Form
- Link with container
- Symbol behavior application to container (move to x with xpositionreference)

Important changes
- Remove SelectedContainer from HistoryState, meaning that it will be slower for each load but will be faster for each operations* (SetHistory, SelectContainer, DeleteContainer, SymbolOperations)
- ElementsSidebar now opens with isSidebarOpen meaning that both sidebar will open on toggle
- Moved camelize, transformX, restoreX to different modules (stringtools.ts, svg.ts)

src/utils/svg.ts

@@ -0,0 +1,21 @@
+import { XPositionReference } from '../Enums/XPositionReference';
+
+export function transformX(x: number, width: number, xPositionReference = XPositionReference.Left): number {
+  let transformedX = x;
+  if (xPositionReference === XPositionReference.Center) {
+    transformedX += width / 2;
+  } else if (xPositionReference === XPositionReference.Right) {
+    transformedX += width;
+  }
+  return transformedX;
+}
+
+export function restoreX(x: number, width: number, xPositionReference = XPositionReference.Left): number {
+  let transformedX = x;
+  if (xPositionReference === XPositionReference.Center) {
+    transformedX -= width / 2;
+  } else if (xPositionReference === XPositionReference.Right) {
+    transformedX -= width;
+  }
+  return transformedX;
+}