Xenopsd

The xenops daemon

This is an attempt to improve the architecture of the XCP toolstack by splitting *domain management* into a separate service, known as the *xenops daemon*. This should have the following advantages:

1. it helps untangle the domain management code from the rest of xapi (which will focus on multi-host resource pool management)
2. it forces us to be explicit about the interface xapi needs, making the future libxl port more predictable and likely to succeed
3. it forces us to be explicit about the interface xenopsd needs, preventing (for example) the accidental insertion of a expensive RPC to a remote host through an internal xapi interface in a hot codepath.

Design overview