Alter plan parameters in plan repositories to be Sets where appropriate

[DiamondJoseph]

Many plans currently take a list of devices, where actually the uniqueness of the devices is assumed and required.

These lists should be replaced with a set and handling of the plan should be updated to allow for metadata to pass an order of the devices if it is required.

This will make the returned schema for a plan easier to reflect in a generated UI.

[DiamondJoseph]

Done during the move of the plans from dls-bluesky-core to dodal
#645