DATABASE_TO_JSON_ERROR due to !1887 (unknown element in hosts-database/config-database: read-timeout and write-timeout)

!1887 (merged) added read-timeout and write-timeout fields without updating src/lib/database/database_connection.cc. This results in the following error message in kea-dhcp4.log when issuing config-get through kea-shell:

2023-01-30 10:23:04.893 ERROR [kea-dhcp4.database/1441.140255010749440] DATABASE_TO_JSON_ERROR Internal logic error: unknown unknown element found in state: read-timeout @@Missing logger placeholder '%3' for value '2'@@
2023-01-30 10:23:04.893 ERROR [kea-dhcp4.database/1441.140255010749440] DATABASE_TO_JSON_ERROR Internal logic error: unknown unknown element found in state: write-timeout @@Missing logger placeholder '%3' for value '2'@@
2023-01-30 10:23:04.893 ERROR [kea-dhcp4.database/1441.140255010749440] DATABASE_TO_JSON_ERROR Internal logic error: unknown unknown element found in state: read-timeout @@Missing logger placeholder '%3' for value '2'@@
2023-01-30 10:23:04.893 ERROR [kea-dhcp4.database/1441.140255010749440] DATABASE_TO_JSON_ERROR Internal logic error: unknown unknown element found in state: write-timeout @@Missing logger placeholder '%3' for value '2'@@

I believe this could be fixed by adding these keywords to https://gitlab.isc.org/isc-projects/kea/-/blob/master/src/lib/database/database_connection.cc#L226-231, but I did not have time to test this yet. This will also need to be ported to my !1907 (closed), once it is in master.

Config needed for reproduction:

{
    "Dhcp4": {
        "hosts-database": {
            "type": "mysql",
            "read-timeout": 2,
            "write-timeout": 2
        },
        "config-control": {
            "config-databases": [
                {
                    "type": "mysql",
                    "read-timeout": 2,
                    "write-timeout": 2
                }
            ]
        }
}

Expected results:

• the exported config should match the input.

Actual results:

• read-timeout and write-timeout of both sections will be missing on the configuration exported with config-get.