- Get rid of @not_in_api, exchange for explicit @api() decorator.
- Old @no_payload decorator becomes an argument (keyword-only).
- Factor out AbstractQubesMgmt class to be a base class for other mgmt
backends.
- Use async def instead of @asyncio.coroutine.
QubesOS/qubes-issues#2622
This also means we don't check if a VM with given name (in case of
VMProperty) exists in the system, at this stage. But this is ok, lets
not duplicate work of property setter.
QubesOS/qubes-issues#2622
In theory any call could modify config (through events), but lets keep
writes to qubes.xml low. In any case, qubes.xml will be eventually
written (either at next config-modifying call, or daemon exit).
Sanitization of input value is tricky here, and also very important at
the same time. If property define value type (and it's something more
specific than 'str'), use that. Otherwise allow only printable ASCII
characters, and let appropriate event and setter handle value.
At this point I've reviewed all QubesVM properties in this category and
added appropriate setters where needed.
QubesOS/qubes-issues#2622
