Use localized links in localized docs

[ghost]

The following documentation is currently translated:

• SLES [partly]
• SLED [partly]
• SLE-HA [partly]
• SES [fully]

Where possible, we should try to use localized links to other translated SUSE documentation in within the translated documents.

Getting there is a bit of an issue, as we just dump the localized versions into a branch once per release. Meaning the documents go en->translated version for every single release, without any continuous history across releases.