Added a httponly option for HTMLResponse.set_cookie

[lopezvoliver]

Following the discussion in #799, I added an option configurable through an environment variable SOLARA_SESSION_HTTP_ONLY, and passing this to the httponly option in HTMLResponse.

As discussed, this change is backwards compatible because it defaults to False.

Here we can verify the httpOnly attribute of the solara-session-id cookie using Developer tools:

and here's another screenshot showing the behavior when setting the environment variable SOLARA_SESSION_HTTP_ONLY=True:

Note that the cookie no longer appears in document.cookie.

Thus, this PR makes it possible for a solara-based application to comply with cwe 402

[iisakkirotko]

Looks good to me. Thanks a lot for the PR @lopezvoliver!

[maartenbreddels]

Awesome, I think we can make it a bit simpler even, what do you think?

[lopezvoliver]

Awesome, I think we can make it a bit simpler even, what do you think?

Yes, and this is also consistent with the default False value in starlette.