refactor(queue): unify Queue::new() to return Result

[CepheusC]

This pr makes two changes to the bandwidth queue system:

1. Unify Queue::new() signature — Change all queue implementations (InfiniteQueue, DropTailQueue, DropHeadQueue, CoDelQueue) to return Result<Self, Error> instead of a direct instance.
2. Update all interfaces related to Queue::new().

[BobAnkh]

@CepheusC Do not include pie and red in this PR.

[Centaurus99]

1. Move new into PacketQueue trait since impl_bw_cell_into_factory! macros already assume a fixed new(config) -> Result<Self, _> signature per queue.
2. Replace the per-type From<XxxQueueConfig> impls with a single impl TryFrom on PacketQueue trait.
3. @BobAnkh Is .expect() in impl Default for XxxQueue (e.g. droptail.rs:71) fine to keep, given all four queues actually never fail here?

[BobAnkh]

1. Move new into PacketQueue trait since impl_bw_cell_into_factory! macros already assume a fixed new(config) -> Result<Self, _> signature per queue.
2. Replace the per-type From<XxxQueueConfig> impls with a single impl TryFrom on PacketQueue trait.
3. @BobAnkh Is .expect() in impl Default for XxxQueue (e.g. droptail.rs:71) fine to keep, given all four queues actually never fail here?

Yes, it is fine to keep except for never-fail condition.

[Centaurus99]

LGTM.