Is your feature request related to a problem? Please describe

Using onlynet and deciding outbound connection types should be easy for GUI users

Describe the solution you'd like

Additional context

There are few issues with onlynet and they should be fixed with bitcoin/bitcoin#22834

Possible combinations are:

ipv4
ipv6
onion
i2p

onion-ipv4
onion-ipv6
i2p-ipv4
i2p-ipv6
i2p-onion
ipv6-ipv4

onion-ipv6-ipv4
i2p-ipv6-ipv4
i2p-onion-ipv4
i2p-onion-ipv6

Ignoring i2p-onion-ipv6-ipv4 because it will be same as not using onlynet. So default can be all options checked if there is nothing mentioned in bitcoin.conf.