feat: add silent flag and fix dry run with prerequisites (#767)

## Description

Closes open-component-model/ocm-project#37


## What type of PR is this? (check all applicable)

- [ ] 🍕 Feature
- [ ] 🎇 Restructuring
- [ ] 🐛 Bug Fix
- [ ] 📝 Documentation Update
- [ ] 🎨 Style
- [ ] 🧑‍💻 Code Refactor
- [ ] 🔥 Performance Improvements
- [ ] ✅ Test
- [ ] 🤖 Build
- [ ] 🔁 CI
- [ ] 📦 Chore (Release)
- [ ] ⏩ Revert

## Related Tickets & Documents

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## Screenshots

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## Added tests?

- [ ] 👍 yes
- [ ] 🙅 no, because they aren't needed
- [ ] 🙋 no, because I need help
- [ ] Separate ticket for tests # (issue/pr)

Please describe the tests that you ran to verify your changes. Provide
instructions so we can reproduce. Please also list any relevant details
for your test configuration


## Added to documentation?

- [ ] 📜 README.md
- [ ] 🙅 no documentation needed

## Checklist:

- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation
- [ ] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

Co-authored-by: Hilmar Falkenberg <hilmar.falkenberg@sap.com>

cmds/ocm/commands/controllercmds/common/manifests.go

@@ -98,6 +98,7 @@ func fetchObjects(ctx context.Context, octx clictx.Context, releaseURL, baseURL,
 		}
 
 		out.Outf(octx, string(content))
+
 		return nil, nil
 	}
 	out.Outf(octx, "► applying to cluster...\n")

cmds/ocm/commands/controllercmds/install/cmd.go

@@ -41,6 +41,7 @@ type Command struct {
 	DryRun                   bool
 	SkipPreFlightCheck       bool
 	InstallPrerequisites     bool
+	Silent                   bool
 	SM                       *ssa.ResourceManager
 }
 
@@ -71,13 +72,21 @@ func (o *Command) AddFlags(set *pflag.FlagSet) {
 	set.BoolVarP(&o.DryRun, "dry-run", "d", false, "if enabled, prints the downloaded manifest file")
 	set.BoolVarP(&o.SkipPreFlightCheck, "skip-pre-flight-check", "s", false, "skip the pre-flight check for clusters")
 	set.BoolVarP(&o.InstallPrerequisites, "install-prerequisites", "i", true, "install prerequisites required by ocm-controller")
+	set.BoolVarP(&o.Silent, "silent", "l", false, "don't fail on error")
 }
 
 func (o *Command) Complete(args []string) error {
 	return nil
 }
 
-func (o *Command) Run() error {
+func (o *Command) Run() (err error) {
+	defer func() {
+		// don't return any errors
+		if o.Silent {
+			err = nil
+		}
+	}()
+
 	kubeconfigArgs := genericclioptions.NewConfigFlags(false)
 	sm, err := NewResourceManager(kubeconfigArgs)
 	if err != nil {

cmds/ocm/commands/controllercmds/install/install_cert_manager.go

@@ -25,6 +25,11 @@ func (o *Command) installPrerequisites(ctx context.Context) error {
 	}
 
 	out.Outf(o.Context, "✔ cert-manager successfully installed\n")
+
+	if o.DryRun {
+		return nil
+	}
+
 	out.Outf(o.Context, "► creating certificate for internal registry\n")
 
 	if err := o.createRegistryCertificate(); err != nil {

cmds/ocm/commands/controllercmds/uninstall/cmd.go

@@ -35,6 +35,7 @@ type Command struct {
 	CertManagerVersion       string
 	SM                       *ssa.ResourceManager
 	UninstallPrerequisites   bool
+	Silent                   bool
 	DryRun                   bool
 }
 
@@ -65,13 +66,21 @@ func (o *Command) AddFlags(set *pflag.FlagSet) {
 	set.DurationVarP(&o.Timeout, "timeout", "t", 1*time.Minute, "maximum time to wait for deployment to be ready")
 	set.BoolVarP(&o.UninstallPrerequisites, "uninstall-prerequisites", "p", false, "uninstall prerequisites required by ocm-controller")
 	set.BoolVarP(&o.DryRun, "dry-run", "d", false, "if enabled, prints the downloaded manifest file")
+	set.BoolVarP(&o.Silent, "silent", "l", false, "don't fail on error")
 }
 
 func (o *Command) Complete(args []string) error {
 	return nil
 }
 
-func (o *Command) Run() error {
+func (o *Command) Run() (err error) {
+	defer func() {
+		// don't return any errors
+		if o.Silent {
+			err = nil
+		}
+	}()
+
 	kubeconfigArgs := genericclioptions.NewConfigFlags(false)
 	sm, err := NewResourceManager(kubeconfigArgs)
 	if err != nil {