Adding a preinstallation checklist

[scoopex]

This list describes some aspects (without claiming to be exhaustive) that should be clarified before a pilot and at least before production installation.

The aim of this list is to reduce:

• Projects that could be more successful
• Long project waiting/implementation times
• Unexpected errors or difficulties
• Major restructuring work soon after the system was initially put into operation
• Unexpected issues that have a major impact on costs.

[garloff]

This is a good start, IMVHO.

[garloff]

Sidenote on the link-checker CI failure:

• The document references its own source in a request to contribute, which makes sense.
• The doc source does not exist prior to merging this PR
  So the failure is harmless.