QM driver remaining issues for first 0.2 release

[stavros11]

#933 (comment)

• Baking: support for durations that are not multiple of 4ns. Now we also need to handle the case of non-integer durations, potentially by casting to int and raising a warning. See also discussion in QM duration sweeper using multiple waveforms #979 (comment) (Done in Add baking in QM driver #1005)
• Unrolling: unroll_sequences now needs to be called by the driver. (Done in Unrolling and parallel sweeps for QM #1008)
• Parallel sweeps: the sweeper structure in the driver is updated with this in mind, however I did not fully implement it for the case len(parallel_sweepers) > 1 mainly because there is no qibocal routine using this. We may end up needing it for all routines if we drop sweeper types (Drop SweeperType #540). (Done in Unrolling and parallel sweeps for QM #1008)

[stavros11]

All listed features are now implemented, with the corresponding PRs linked in the first comment.