Quadlet - Error when units define User, Group, or DynamicUser in Serv…

[AgentEpsilon]

…ice group

Fixes: #26543

Does this PR introduce a user-facing change?

Added: Quadlet generator will now fail with a descriptive error message if a unit defines User, Group, or DynamicUser in its Service group.
	Users created by systemd in this way this way cannot run podman, so this is an improvement over the current behavior - generating a systemd service that will fail.

[Luap99]

Thanks overall this seems like a good idea.

@mheon @baude @ygalblum WDYT?

[AgentEpsilon]

Update: Per discussion, changed to a warning instead of an error. Since initServiceUnitFile doesn't currently log any warnings, rather than refactor a large amount of quadlet.go I lifted the logic out to main.go, similar to the warnIfAmbiguousName func adjacent to it.

[packit-as-a-service]

[NON-BLOCKING] Packit jobs failed. @containers/packit-build please check. Everyone else, feel free to ignore.

[Luap99]

LGTM

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: AgentEpsilon, Luap99

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [Luap99]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[ygalblum]

LGTM. @Luap99 can we merge without these two checks that seem stuck?

[Luap99]

yes, we have merge protection for the stuff that is blocking (everything in cirrus basically). The packit tasks are optional.
/lgtm