Parse ASCIIart device layout into DeviceSpecification proto.

This function assumes that all pairs of adjacent qubits are valid targets for two-qubit gates.

ascii_grid ASCII version of the grid (see _parse_device for details).
gate_sets Gate sets that define the translation between gate ids and cirq Gate objects.
durations_picos A map from gate ids to gate durations in picoseconds.
out If given, populate this proto, otherwise create a new proto.