Add switches to the host init script to toggle legacy behaviour

[dxapd]

add two new flags for toggling static resource initialization as well as running cvdalloc's init (which is to be implemented in the final PR in this series).

due to the way nftables works, cvdalloc also needs to do a small amount of install-time init (namely, creating its tables and chains). that code is better off living inside the cvdalloc binary, so we have the init script, which is our one hook point into install and uninstall, invoke it at exactly those times.

this change, as is, should be a no-op. the code enclosed within the if [ "${allocate_static_resources}" = "1" ]; then branches is the code we hope to delete one day, but until that day it will remain.

[3405691582]

due to the way nftables works, cvdalloc also needs to do a small amount of install-time init (namely, creating its tables and chains).

Can we do this without having to do this at init? Can we interrogate nftables and see if our tables and chains exist, and if not, install them then?