Extended info store needs to store explict relay sub-option values for Bulk LeaseQuery

As called for in the BLQ design, https://gitlab.isc.org/isc-projects/kea/-/wikis/Designs/Bulk-LeaseQuery-Design#query-data-requirements, the extended info storage in AllocationEngine for both v4 and v6 needs to store explicit values for relay-id, remote-id (when they exist):

For v4:

"ISC":
{
    "relay-agent-info": 0x...,  // packed contents of client's RAI (option 82)
    "remote-id"  : 0x...        // extracted from RAI                                <--- NEW
    "relay-id"   : 0x...        // extracted from RAI                                <--- NEW
    ...
}

and v6 (per relay layer):

"ISC":
{
    "relay-info":
    [
    {
        "hop": 123,
        "link": "IP-address",
        "peer": "IP-address",
        "options": 0x....       // relay sub-options except relay message option
        "remote-id"  : 0x...    // extracted from "options"                         <--- NEW
        "relay-id"   : 0x...    // extracted from "options"                         <--- NEW
    },
    :
    ],
}