Change the default header of X-Robots-Tag to "noindex, nofollow"

[stavros-k]

---

• I have read the contributing guideline and understand that I have made the correct modifications

---

Description:

NC 26 shows the bellow warning:

Benefits of this PR and context:

Partially fixes#298

Follow upstream nextcloud suggestions

How Has This Been Tested?

Manually made the changes on my instance, restarted it and warning was gone.
Also checked headers in the dev tools in browser

Source / References:

[github-actions]

Thanks for opening this pull request! Be sure to follow the pull request template!

[LinuxServer-CI]

I am a bot, here are the test results for this PR:
https://ci-tests.linuxserver.io/lspipepr/nextcloud/26.0.0-pkg-ff88fd2c-pr-299/index.html
https://ci-tests.linuxserver.io/lspipepr/nextcloud/26.0.0-pkg-ff88fd2c-pr-299/shellcheck-result.xml

[thespad]

The X-Robots-Tag header is set to none, this is equivalent to noindex, nofollow (source), so I have no idea why Nextcloud have decided to pointlessly change their detection for this.

[aptalca]

Pretty sure when it comes to header detection, Nextcloud looks for an exact match of whatever parameter they like, and if it doesn't match exactly, it complains. It's pretty poor implementation.

[thespad]

Yeah, but in previous versions they were happy with none, because that's what we've used for ages, which suggests they've changed what they're looking for.

[stavros-k]

nextcloud/server#36689

While "none" is indeed equivalent to "noindex, nofollow" for Google, but seems to be not supported by Bing and probably other search engines.