feat: make search path for BinaryFinder customizable.

[exi]

• Resolves: Configurable binary path for Mailer/etc #43922

Summary

This feature is important for nextcloud running on distributions like NixOS, where all the standard
search paths do not exist.

I chose to make the list overridable instead of appendable because having a default list that always gets
applied might cause reproducibility issues on distros like NixOS where we have multiple versions
of the same binary at the same time.

This fixes issue #43922

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Documentation (manuals or wiki) has been updated or is not required

[exi]

@kesselb i force pushed a change to address the workflow failures. It seems to need another review/approval now

[exi]

@kesselb every time, all the tests checking out submodules fail for branches that don't originate from github.com/nextcloud. Is this something I'm doing wrong, or are the CI checks just funky?

I don't know what I did to cause the errors in the failing actions.

[skjnldsv]

@exi the cypress will fail, it's broken for forks.

resolved

[kesselb]

Hi @exi,

I hope you are still with us, I'm sorry it's taking so long 🙈

We migrated to spdx copyright headers meanwhile, and therefore the new test file needs an update.

Example:

/**
 * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
 * SPDX-License-Identifier: AGPL-3.0-or-later
 */

And then another rebase would be nice to have a recent CI run and the remove the merge commits.
Fyi we pushed to your branch/fork through GitHub.

[exi]

@kesselb I applied one suggestion and rebased it. should be good now.

[exi]

@kesselb fixed the new type error and reverted it to the "$result === null" check as before.

[kesselb]

@exi I fear we need another rebase/squash because "Update tests/lib/BinaryFinderTest.php" is not a conventional commit 🙈

[exi]

@kesselb done

[kesselb]

I rebased the branch via GitHub to pull a fix for our CI pipeline.

[kesselb]

The failing CI is wip, nothing needs to be done here for now.

I will rebase the pr again, once our issues with the CI are resolved.

(Please ping me if I haven't done that within one week)

[icewind1991]

rebased

[kesselb]

I force-pushed to your branch to fix some code style issues.
We updated our coding-style just yesterday.

[welcome]

Thanks for your first pull request and welcome to the community! Feel free to keep them coming! If you are looking for issues to tackle then have a look at this selection: https://github.com/nextcloud/server/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22