If there is only one AC, roaming does not require special configuration, but if there are
two ACs controlling the AP then the following configuration is required to complete the inter-AC roaming.
In a WLAN network, roaming is not possible between any two ACs. By configuring a roaming group to group different ACs,
STAs can roam between ACs in the same roaming group.
The STA roams between ACs in the same roaming group, and the AC in the roaming group needs to be able to identify other ACs in the group.
Local configuration: If the AC does not specify a roaming group server, you need to configure roaming groups on each AC in the roaming group
and add member ACs.
