Simplify unikernel deployment

[PizieDust]

Currently the deploy form tries to get as many parameters configured as possible.
A better user experience will be to let them configure only what is necessary, and the rest of the configurations be put under an Advanced Configuration heading that will then let the user jump into more parameters.

Secondly, if a user is only given 1 cpu_id to deploy on, there's no need allowing them a dropdown to select out of 1 option. This can be auto-selected, and this also applies to other resources i.e block devices, network interfaces.

Memory should default to 32MB, unless the user used advanced configuration to modify it.

cc @hannesm

[hannesm]

This is very vague, I tried to explain it in the meeting:

• what is really required for deployment? A name and a unikernel image (or link to it deploy unikernel: allow a reference to a job on builds.robur.coop instead of uploading the image manually #130)
• all the rest should be auto-filled (and not exist in the basic/simple form -- such as CPU ID (can be randomly chosen amongst those available; memory; startup priority, fail behaviour (should default to restart), force create (should default to not))
• now if deploy unikernel: allow a reference to a job on builds.robur.coop instead of uploading the image manually #130 is in place, the unikernel-needed network devices could be auto-filled, esp. if you have matching names (service=service/management=management, ...)
• for block devices, once deploy unikernel: allow a reference to a job on builds.robur.coop instead of uploading the image manually #130 is there (and we know the manifest of the unikernel), we could select the block devices from a dropdown and have a button "create a fresh block device" (named after the unikernel, size = ??)
• arguments currently require setting the IP address and gateway -- hopefully soon we can use DHCP for this

I hope this makes it clear. This issue is not easily done - it has some dependencies and we have to figure out our deployment.