sylva-units: support uninterpreted values, aka "raw" values

This MR is a proposed solution for #1307 (closed)

It is proposed as an alternative to !4080 (closed) based on the idea exposed here, and even further simplified:

• for a value specified as raw by the user, each occurrence of {{ is replaced by a special "shield character" (I used ❮) to avoid the {{ triggering golang template interpretation
• the shield character is substituted again by }} right before producing the final manifests

The syntax for raw values proposed in this MR is the following:

Example

units:
  foo:
    helmrelease_spec:
      values:
         myFooSetting:
           (raw): my custom stuff {{ .bar }}

I'm proposing this dict syntax because it has one nice advantage: we can refer to {{ .Values.foo }} without having to know if foo is raw or not; in either case it will exist and this will not depend on the order of interpretation. We wouldn't have this advantage with a syntax where the information that the content is raw was in the key as in a previous proposal ((raw)foo: my custom stuff {{ .bar }}).

Would Close #1307 (closed)

CI configuration

Below you can choose test deployment variants to run in this MR's CI.

Click to open to CI configuration

Legend:

Icon	Meaning	Available values
☁️	Infra Provider	capd, capo, capm3
🚀	Bootstrap Provider	kubeadm (alias kadm), rke2
🐧	Node OS	ubuntu, suse
🛠️	Deployment Options	light-deploy, dev-sources, ha, misc, maxsurge-0, logging
🎬	Pipeline Scenarios	Available scenario list and description

• 🎬 preview ☁️ capd 🚀 kadm 🐧 ubuntu

• 🎬 preview ☁️ capo 🚀 rke2 🐧 suse

• 🎬 preview ☁️ capm3 🚀 rke2 🐧 ubuntu

• ☁️ capd 🚀 kadm 🛠️ light-deploy 🐧 ubuntu

• ☁️ capd 🚀 rke2 🛠️ light-deploy 🐧 suse

• ☁️ capo 🚀 rke2 🐧 suse

• ☁️ capo 🚀 kadm 🐧 ubuntu

• ☁️ capo 🚀 rke2 🎬 rolling-update 🛠️ ha 🐧 ubuntu

• ☁️ capo 🚀 kadm 🎬 wkld-k8s-upgrade 🐧 ubuntu

• ☁️ capo 🚀 rke2 🎬 rolling-update-no-wkld 🛠️ ha,misc 🐧 suse

• ☁️ capo 🚀 rke2 🎬 sylva-upgrade-from-1.3.x 🛠️ ha,misc 🐧 ubuntu

• ☁️ capm3 🚀 rke2 🐧 suse

• ☁️ capm3 🚀 kadm 🐧 ubuntu

• ☁️ capm3 🚀 kadm 🎬 rolling-update-no-wkld 🛠️ ha,misc 🐧 ubuntu

• ☁️ capm3 🚀 rke2 🎬 wkld-k8s-upgrade 🛠️ ha 🐧 suse

• ☁️ capm3 🚀 kadm 🎬 rolling-update 🛠️ ha 🐧 ubuntu

• ☁️ capm3 🚀 rke2 🎬 sylva-upgrade-from-1.3.x 🛠️ misc,ha 🐧 suse

• ☁️ capm3 🚀 kadm 🎬 rolling-update 🛠️ ha 🐧 suse

Global config for deployment pipelines

• autorun pipelines
• allow failure on pipelines
• record sylvactl events

Notes:

• Enabling autorun will make deployment pipelines to be run automatically without human interaction
• Disabling allow failure will make deployment pipelines mandatory for pipeline success.
• if both autorun and allow failure are disabled, deployment pipelines will need manual triggering but will be blocking the pipeline

Be aware: after configuration change, pipeline is not triggered automatically. Please run it manually (by clicking the run pipeline button in Pipelines tab) or push new code.