Support action-triggered site vpn rule for a specific client

[lts-rad]

• we can do site vpn on schedules
• we can do site vpns by tags

idea:

• add a tag to a client when domain name is looked up or traffic hits the site VPN from a client

• this would allow for moving all of that clients traffic to the site vpn as a result

next:

• let this rule expire after some time if the trigger has not activated