limactl info: report driver capabilities #5582

Description

There is no way to ask what a vmType supports. Snapshots are one example: qemu and krunkit implement SnapshotManager, vz/wsl2/hcs return "unimplemented". Anything that needs to know has to hardcode a list of vmTypes, e.g. the qemu | krunkit whitelist in hack/bats/tests/snapshot.bats.

driver.DriverFeatures mixes fixed capabilities with instance state, so it cannot be reported directly by limactl info.

Proposal: add separate fixed capability flags (starting with canSnapshot) and report each driver's capabilities in limactl info under vmTypesEx. Internal drivers are free to query. External drivers must be started, so limactl info has to spawn lima-driver-* once, read Info(), and stop it again — with a timeout, and without failing the command if a driver cannot be started.

Context: #5534