A couple of ideas:

• ingénieur généraliste
• ingénieur polyvalent

Note that the referenced Full Stack Developer definition simply describes a software developer mastering current & fashionable web technologies.
A developer is not necessarily an engineer, not necessarily an architect.
Therefore, I would simply translate as “développeur technologies web”.
If the job requires it, use “ingénieur confirmé technologies web” or even “ingénieur technologies web très confirmé”.

In any case, “Full Stack Developer” is just a buzzword. You can as well translate it as “développeur Full Stack”, everybody will recognize the buzzword…

You may want to see the “stack” in french as a “cycle” because in software development if you traverse the full stack you actually made a cycle in the development or running of the project (especially if you work with iterations).

So I was thinking of something like

• Ingénieur cycle complet
• Ingénieur cycle de vie complet

but that doesn’t “sounds good” in french.