php8: Compatibility fixes

app/dashboard/widgets/changelog.php

app/subnets/addresses/address-modify-submit.php

app/subnets/addresses/print-address-table.php

app/subnets/subnet-details/subnet-details.php

app/temp_share/subnet-details.php

app/tools/changelog/changelog-print.php

app/tools/changelog/show-popup.php

app/tools/customers/customer/objects/ipaddresses.php

app/tools/vlan/vlan-details.php

functions/classes/class.Common.php

functions/classes/class.Log.php