feat(exp): add `actionutil.AllForResource`

[jooola]

Allow the users to fetch actions related to a specific resource.

This may be used as follows:

actions, err := actionutil.AllForResource(ctx,
    client.Firewall.Action,
    hcloud.ActionListOpts{Status: []hcloud.ActionStatus{hcloud.ActionStatusRunning}},
    hcloud.ActionResourceTypeServer, server.ID,
)
if err != nil {
    return err
}
if err := client.Action.WaitFor(ctx, actions...); err != nil {
    return err
}

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 77.77778% with 2 lines in your changes missing coverage. Please review.

Project coverage is 71.47%. Comparing base (743eabb) to head (824cb91).

Files	Patch %	Lines
hcloud/exp/actionutil/actions.go	77.77%	1 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #522 +/- ## ========================================== + Coverage 71.46% 71.47% +0.01% ========================================== Files 46 46 Lines 3935 3944 +9 ========================================== + Hits 2812 2819 +7 - Misses 710 711 +1 - Partials 413 414 +1 ```

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[jooola]

Here is an example: https://github.com/hetznercloud/packer-plugin-hcloud/compare/main...tmp-use-actionutil.allforresource