fix(systemd-resolved): add systemd-resolve user

[Cornelicorn]

This pull request adds the systemd-resolve user to initramfs when using the systemd-resolved module.

Changes

Checklist

• I have tested it locally
• I have reviewed and updated any documentation if relevant
• I am providing new code and test(s) for it

Fixes #1656

[johannbg]

@Cornelicorn hmm we dont parse/grep and or otherwise use users from /etc/passwd anymore anyways something must have changed in systemd upstream ( like systemd finally splitting all their users into seperated sysusers files, which then requires fixes in more places since probably more users are missing ), all the systemd users should currently be provided via systemd-sysusers module, which this module is dependent upon.

If systemd upstream has done the right thing ( by splitting it's users into seperated sysuser files ) then we need to try to included that sd-resolve sysuser file from the underlying OS probably with a fallback on our own include sd-resolve sysuser file if the sysuser file is not found.

That fix requires adding "$sysusers"/systemd-resolve.conf in the install() section of the module and "$sysusersconfdir"/systemd-resolve.conf in the hostonly section of the install() section and we probably should be adding that sysuser file to the module as well.

[Cornelicorn]

Superseeded by #1658

[johannbg]

Somewhat permature closure since we still need to include the new systemd-resolve.conf file otherwise this will just break again with the next sd release

[Cornelicorn]

Somewhat permature closure since we still need to include the new systemd-resolve.conf file otherwise this will just break again with the next sd release

Ah right, forgot about the change in systemd sysuser configs. But maybe this should be tackled in a new PR together with all other sysuser configs.

[johannbg]

Agreed