Add application name option

[leonvogt]

Currently this Dev Tools makes an assumption, that your Stimulus application is assigned to window.Stimulus and Turbo to window.Turbo.
Since you can customize these names, it would be nice to have configurable options for the Stimulus and Turbo application name.

The only tricky part will probably be to the fetch the application name in the inject.js file, since we don't have access to the chrome.storage API.
One option would be to define a meta tag with the application name, before loading the inject.js file.