Feature: Add online svg editor

Provide an online svg editor.

On a picture, add a button to open an online svg editor where you can add line of routes and waypoints. Then saving creates a new picture with same associations and a link to the original picture.

See for example [nature.baikal](https://nature.baikal.ru/phs/ph.shtml?id=8332&ref=peaks/kupol/phs) for svg with links to objects.

Maybe we can use https://github.com/Yqnn/svg-path-editor or https://github.com/SVG-Edit/svgedit/ ?

Start by reviewing the picture view and its save flow, then evaluate the proposed svg-path-editor and SVG-Edit options. Define how route lines and waypoints are created, how associations are copied, and how the original picture is linked before implementation; no files or tests are named.

Written by the indexing model from the issue text.