feat: (IAC-1117) WIP: air gap installation and additionnal fixes

[momiji]

As explained in #372, this is a WIP PR for all changes required to have a better air gapped installation.

Changes:

• add V4_CFG_CERTS for certs.zip file location
• prevent viya4-orders-cli when all 3 required order files are configured (certs, license, deployment assets)
• add V4_CFG_URL for repository warehouse url, defaults to https://ses.sas.download/ses
• updated docs for new variables
• new doc AirGapInstallation.md for what we've discovered so far - sorry for my bad/mean english wordings

We're still working on first installation, new items may be added later.

[momiji]

While working on updating to 2023.08 we had time to check if it was possible to inject the repositoryWarehouse.url after the sasdeployment.yaml generation.

It is indeed possible, hence this is not absolutely required, as it is possible to do so using tools like xjq or yq (jq for yaml files).

$ cat sasdeployment.yaml | xjq -y \
    '(select(.kind=="SASDeployment").spec.repositoryWarehouse.url=$REPOSITORY)' \
    --arg REPOSITORY "$REPOSITORY"

However I still believe it is better to be able to do it automatically, of course :)