Discourage usage of ARKINDEX_API_TOKEN

Closes #1716 (closed)

Also updated the system checks wiki page to add the new warning.

changed milestone to %Arkindex 1.6.1

requested review from @babadie

assigned to @erouchet

added 2 commits

• 38a84a1f - 1 commit from branch master
• 6652b69d - Discourage usage of ARKINDEX_API_TOKEN

Compare with previous version

merged