fix: relative asset paths

[konradmichalik]

Subject

We're using symfony instances on our staging system in subdirectories. Unfortunately we ran into the problem, that the public assets of the sonataform bundle points to absolute paths.

I think the paths need an relative "./" to be more flexible. See entrypoints.json and manifest.json.

I'm not so familiar with the webpack config, but I think changing the public path may deals with this fact, see webpack.config.js.

Closes #480 .

Changelog

Changed

Added relative dot to public path within webpack config.