docs: implement KLT -> Keptn name change

[StackScribe]

Closes #1848

TO BE MERGED ONLY BY @thisthat !!!! in coordination with public announcements and the related blog post

Files that are modified or were checked

Main documentation sections (added when the change is drafted)

• intro-klt
  This is name change only, but this section must be rewritten by the time of publication. See Rewrite intro-klt for Sept 7 rollout #2005
• getting-started
• install
• operate
• implementing
• tutorials
• concepts/architecture
• yaml-crd-ref
• troubleshooting
• migrate

Contributing guide

• docs
• general
• software

API/CRD autogenerated docs

• lifecycle/v1alpha3
• lifecycle/v1alpha2 (no instances)
• lifecycle/v1alpha1 (no instances)
• options/v1alpha1 (no instances)
• metrics-operator/api/v1alpha3 (no instances)
• metrics-operator/api/v1alpha2 (no instances)
• metrics-operator/api/v1alpha1 (no instances)

README's

• main (lifecycle-toolkit)
• examples/sample-app
• examples/support/argo
• examples/support/metrics
• examples/support/observability
• helm/chart
• klt-cert-manager
  • Includes mention of Lifecycle Toolkit operator Versions 0.6.0. Does that remain the same?
• lifecycle-operator (no instances)
• metrics-operator (no instances)
• runtimes/deno-runtime
  • KeptnTask reference should link to one of the reference sections
• runtimes/python-runtime

Issues

Needed to complete this PR

• How do we handle links to videos that include "Keptn Lifecycle Toolkit" or "KLT" in their titles?
• In Use Keptn Automatic App Discovery, we have a sample KeptnApp resource that includes the following:

  apiVersion: lifecycle.keptn.sh/v1alpha2
  kind: KeptnApp
  metadata:
    name: podtato-head
    namespace: podtato-kubectl
    annotations:
      app.kubernetes.io/managed-by: "klt"

   Is it going to be `managed-by: "klt"` or `managed-by: "keptn"`?
   Answer: it should be "keptn" but that requires modifying the Helm Chart, so https://github.com/keptn/lifecycle-toolkit/issues/2015 

* The graphic in concepts/architecture/components references `KLTComonentKeptn` and `KLTComponents`.   Should those be renamed or stay as is?

   Answer: rename those strings on the graphic

* In the main README.md file, is it still "Keptn Application Lifecycle working group"?

### Related issues outside the scope of this PR

* In a Keptn vs Keptn V1 world, I'm not thrilled that the API libraries are named `v1alpha*`.  I assume we will soon be renaming all those libraries to be something other than `alpha` so maybe we address this at that time.
* What happens to the domain name? Right now everyone is linking (PPTs / presentations / web links) to https://lifecycle.keptn.sh/ - will redirects be implemented? (h/t @agardnerIT )

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[codecov]

Codecov Report

Merging #2001 (0434731) into main (14573cd) will increase coverage by 0.03%.
Report is 3 commits behind head on main.
The diff coverage is 95.12%.

❗ Current head 0434731 differs from pull request most recent head 0b59468. Consider uploading reports for the commit 0b59468 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2001      +/-   ##
==========================================
+ Coverage   84.13%   84.16%   +0.03%     
==========================================
  Files         149      150       +1     
  Lines        9531     9525       -6     
==========================================
- Hits         8019     8017       -2     
+ Misses       1225     1223       -2     
+ Partials      287      285       -2     

Files Changed	Coverage Δ
...operator/apis/lifecycle/v1alpha3/keptnapp_types.go	93.33% <ø> (ø)
...r/apis/lifecycle/v1alpha3/keptnevaluation_types.go	97.29% <ø> (ø)
...or/apis/lifecycle/v1alpha3/keptntask_conversion.go	0.00% <0.00%> (ø)
...tor/apis/lifecycle/v1alpha3/keptnworkload_types.go	93.93% <ø> (ø)
...rator/controllers/lifecycle/keptntask/job_utils.go	72.81% <ø> (-0.30%)	⬇️
...r/apis/lifecycle/v1alpha3/keptnappversion_types.go	97.68% <100.00%> (+0.04%)	⬆️
...perator/apis/lifecycle/v1alpha3/keptntask_types.go	97.59% <100.00%> (ø)
.../lifecycle/v1alpha3/keptnworkloadinstance_types.go	95.49% <100.00%> (+0.08%)	⬆️
...controllers/lifecycle/keptntask/runtime_builder.go	70.44% <100.00%> (ø)
...rator/webhooks/pod_mutator/pod_mutating_webhook.go	75.54% <100.00%> (ø)

... and 2 files with indirect coverage changes

Flag	Coverage Δ
certificate-operator	68.55% <ø> (ø)
component-tests	58.48% <100.00%> (-0.59%)	⬇️
lifecycle-operator	84.94% <95.12%> (+0.01%)	⬆️
metrics-operator	85.85% <ø> (ø)
scheduler	32.12% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

[mowies]

I suggest to rename the intro-klt foldername to intro and also the usecase-orchestrate page still has a few occurrences.
This is the page preview for the orchestrate page: https://deploy-preview-2001--keptn-lifecycle-toolkit.netlify.app/docs/intro-klt/usecase-orchestrate/

[agardnerIT]

Pedantic but the CNCF style guide advises "cloud native" uncapitalized unless used in a name: https://github.com/cncf/foundation/blob/main/style-guide.md

[StackScribe]

"I suggest to rename the intro-klt foldername to intro" -- agreed but no filename changes in this PR.

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

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