web: Add 'shield' guide profile + set unconfigured wan to dhcp (if password was set)

The profile works in a similar way as old workflow.
Whether shield workflow is should be used is based on
/proc/cmdline parsing

When setting guide to enabled=false, if password is set and wan
is not configured set wan to dhcp
8 jobs for bare
in 11 minutes and 27 seconds and was queued for 8 seconds