php8.0: Compatibility fixes

app/footer.php

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

app/tools/changelog/changelog-print.php

app/tools/circuits/all-circuits-map.php

app/tools/circuits/logical-circuits/logical-circuits.php

app/tools/circuits/physical-circuits/all-circuits.php

app/tools/circuits/providers/all-providers.php

app/tools/locations/all-locations-map.php

app/tools/multicast-networks/index.php

app/tools/racks/print-racks-map.php

app/tools/racks/print-racks.php

app/tools/vlan/domains.php

app/tools/vrf/all_vrf.php

functions/classes/class.Common.php

functions/classes/class.OpenStreetMap.php

functions/classes/class.Sections.php

functions/classes/class.Subnets.php