docs(install): add install Spinnaker page

[aimeeu]

First PR for refactoring the installation section.

Deleted:

• includes/armory-operator/spin-operator-compat.md (not needed; use operator-compat-matrix.md)
• continuous-deployment/installation/guide/minnaker.md - Armory doesn't support Minnaker anymore

Changed to "draft:true" so not compiled for production:

• continuous-deployment/installation/armory-operator/op-config-kustomize -> replaced by continuous-deployment/installation/armory-operator/install-armorycd
• continuous-deployment/installation/armory-operator/op-quickstart -> replaced by continuous-deployment/installation/armory-operator/quickstart-armorycd
• continuous-deployment/installation/armory-operator/op-config-manifest -> content moved to continuous-deployment/installation/armory-operator/op-manifest-reference/_index.md
• continuous-deployment/installation/armory-operator/quickstart-armorycd (deploy.sh) -- deploy.sh doesn't work as expected for installing the operator; after discussing with Fernando, we don't want to use deploy.sh but I'm leaving the file as draft so I don't lose the info

New install guides:

• continuous-deployment/installation/armory-operator/install-armorycd https://deploy-preview-1872--armory-docs.netlify.app/continuous-deployment/installation/armory-operator/install-armorycd/
• continuous-deployment/installation/armory-operator/install-spinnaker https://deploy-preview-1872--armory-docs.netlify.app/continuous-deployment/installation/armory-operator/install-spinnaker/

New Manage Spinnaker guide:

• https://deploy-preview-1872--armory-docs.netlify.app/continuous-deployment/installation/armory-operator/manage-spinnaker/

Updates:

• continuous-deployment/installation/armory-operator/_index.md added Operator install modes from one of the now draft pages. https://deploy-preview-1872--armory-docs.netlify.app/continuous-deployment/installation/armory-operator/
• continuous-deployment/installation/armory-operator/op-manage-operator.md added install instructions https://deploy-preview-1872--armory-docs.netlify.app/continuous-deployment/installation/armory-operator/op-manage-operator/
• continuous-deployment/installation/_index.md updated Guides section. https://deploy-preview-1872--armory-docs.netlify.app/continuous-deployment/installation/

Test install instructions:

• Armory CD continuous-deployment/installation/armory-operator/install-armorycd https://deploy-preview-1872--armory-docs.netlify.app/continuous-deployment/installation/armory-operator/install-armorycd/ tested on EKS 1.24, Armory 2.28.0, Armory Operator v1.8.6; Operator deploys, CDSH use recipe kustomization-minimum.yml; CDSH DEPLOYMENT FAILS

• Spinnaker continuous-deployment/installation/armory-operator/install-spinnaker https://deploy-preview-1872--armory-docs.netlify.app/continuous-deployment/installation/armory-operator/install-spinnaker/ tested locally with a Kind cluster

Test redirects:

• continuous-deployment/installation/armory-operator/op-config-kustomize -> continuous-deployment/installation/armory-operator/install-armorycd
• continuous-deployment/installation/armory-operator/op-quickstart -> continuous-deployment/installation/armory-operator/install-armorycd
• continuous-deployment/installation/armory-operator/op-config-manifest -> continuous-deployment/installation/armory-operator/op-manifest-reference/_index.md
• /continuous-deployment/installation/armory-operator/op-manage-spinnaker/ -> /continuous-deployment/installation/armory-operator/manage-armorycd/

Partial Jira: DOC-709