Revert "manual-install: add back the nextcloud-aio network"

[szaimen]

Reverts #5666

This is not the correct fix. The correct fix lies somewhere here:

all-in-one/Containers/nextcloud/entrypoint.sh

Lines 596 to 600 in 6e2a14f

	IPv4_ADDRESS="$(dig nextcloud-aio-nextcloud A +short +search | head -1)"
	# Bring it in CIDR notation
	# shellcheck disable=SC2001
	IPv4_ADDRESS="$(echo "$IPv4_ADDRESS" | sed 's|[0-9]\+$|0/16|')"
	php /var/www/html/occ config:system:set trusted_proxies 10 --value="$IPv4_ADDRESS"