docs: better "Add a Secret" guide (#22)

* feat: rename folder 'How to Guides' to 'Guides'

* feat: better add-a-secret docs

* docs: emphasize the importance of installing CLIs in “Introduction”

* feat: add error and remove code block highlight

* docs: complete KV part in "Add a secret"

* docs: reorder kv management related docs

* docs: clarify how to update already existing SPC

* docs: translate comments in English

* docs: add a section reference

* docs: separate creation and configuration of the `SecretProviderClass`

* docs: better "Loading secret as ENV" section

* docs: add working examples

* chore: empty commit

* docs: fix broken link

* docs: add reference for mandatory secret volume mount

Co-authored-by: Tommaso Morganti <[email protected]>

---------

Co-authored-by: Tommaso Morganti <[email protected]>

Author: lorenzocorallo

docs/infrastructure/01-Introduction.md

@@ -23,8 +23,13 @@ Why not a simple VM?
 AKS gives us the flexibility of a 10s pod deployment, reliability (with ArgoCD ensuring all pods are up and running all the time) and allows us to be more precise and clean in our infrastructure, with better monitoring and allocated resources for each application depending on the importance.  
 
 ## About this documentation
+:::important
+Most of the docs explain procedures with the Azure CLI and the Kubernetes CLI.  
+Make sure to [install and configure them](./Tutorials/setup#azure-cli--kubectl) to follow along.  
+Alternatively, you can see the [official Azure documentation](https://learn.microsoft.com/en-us/azure/?product=popular) for how to use the Azure portal.
+:::
 
-The best place to start is going through the [Tutorials](./Tutorials/setup) section to get a high level overview of how things are organized.
 
-If you're looking for a guide on how to achieve a specific outcome, you can look in the [How To Guides](./How%20To%20Guides/Adding%20a%20Secret).
-  
+The best place to start is going through the [Tutorials](./Tutorials/setup) section to get a high level overview of how things are organized.  
+If you're looking for a guide on how to achieve a specific outcome, you can look in the [Guides](./Guides/Add%20a%20Secret).
+