Enable ioapic

[jdevalk]

Fixes #900

[jdevalk]

Of course this should be tested for breakage, we've tested this on a couple machines but they're all 64 bit macs :)

[swalkinshaw]

Never heard of this setting before 🤔

VB docs specially say:

On any host, you should enable the I/O APIC for virtual machines that you intend to use in 64-bit mode. This is especially true for 64-bit Windows VMs. See Section 3.3.2, “"Advanced" tab”. In addition, for 64-bit Windows guests, you should make sure that the VM uses the Intel networking device, since there is no 64-bit driver support for the AMD PCNet card; see Section 6.1, “Virtual networking hardware”.

Considering we only support Ubuntu 64bit guests... seems like a good default. Would be nice for a few other people to test this as well.

[swalkinshaw]

Gave this a quick test and everything seemed fine. Would still like some other people to test. Especially on Windows. @kalenjohnson @QWp6t hint hint

[swalkinshaw]

Thanks for this PR. Replacing it with #913 which adds a few more config options too.